55 MCQ on Quadratic Equation with option and answer with explanation

1 . The general form of a quadratic equation is:

a) ax^3 + bx^2 + cx + d = 0

b) ax^2 + bx + c = 0

c) ax + b = 0

d) None of the above

Answer: b) ax^2 + bx + c = 0

Explanation: The standard form of a quadratic equation is ax^2 + bx + c = 0.

2 . The roots of a quadratic equation are also known as:

a) x-intercepts

b) y-intercepts

c) critical points

d) maximum points

Answer: a) x-intercepts

Explanation: The roots of a quadratic equation are the points where the graph of the quadratic equation intersects the x-axis.

3 . The discriminant of a quadratic equation is:

a) b^2 – 4ac

b) 4ac – b^2

c) 2ab

d) None of the above

Answer: a) b^2 – 4ac

Explanation: The discriminant of a quadratic equation is b^2 – 4ac. It is used to determine the nature of the roots of the equation.

4 . If the discriminant of a quadratic equation is negative, then the roots are:

a) real and equal

b) real and distinct

c) complex and equal

d) complex and distinct

Answer: d) complex and distinct

Explanation: If the discriminant of a quadratic equation is negative, then the roots are complex and distinct.

5 . If the discriminant of a quadratic equation is zero, then the roots are:

a) real and equal

b) real and distinct

c) complex and equal

d) complex and distinct

Answer: a) real and equal

Explanation: If the discriminant of a quadratic equation is zero, then the roots are real and equal.

6 . If the discriminant of a quadratic equation is positive, then the roots are:

a) real and equal

b) real and distinct

c) complex and equal

d) complex and distinct

Answer: b) real and distinct

Explanation: If the discriminant of a quadratic equation is positive, then the roots are real and distinct.

7 . The sum of the roots of a quadratic equation is:

a) -b/a

b) b/a

c) c/a

d) -c/a

Answer: a) -b/a

Explanation: The sum of the roots of a quadratic equation is -b/a.

8 . The product of the roots of a quadratic equation is:

a) -b/a

b) b/a

c) c/a

d) -c/a

Answer: d) -c/a

Explanation: The product of the roots of a quadratic equation is c/a.

9 . The quadratic formula is:

a) x = -b/2a

b) x = -b ± √b^2 – 4ac / 2a

c) x = -c/b

d) None of the above

Answer: b) x = -b ± √b^2 – 4ac / 2a

Explanation: The quadratic formula is used to solve quadratic equations. It is given by x = (-b ± √b^2 – 4ac) / 2a.

10 . If the roots of a quadratic equation are reciprocal of each other, then the equation is:

a) x^2 + 2x + 1 = 0

b) x^2 – 2x + 1 = 0

c) x^2 + x + 1 = 0

d) x^2 – x + 1 = 0

Answer: b) x^2 – 2x + 1 = 0

Explanation: Let the roots of the quadratic equation be a and 1/a. Then the quadratic equation can be written as x^2 – (a + 1/a)x + 1 = 0. Since the roots are reciprocal of each other, we have a + 1/a = 2 or a = 1. Substituting a = 1 in the equation, we get x^2 – 2x + 1 = 0.

11 . The equation x^2 – 3x + 2 = 0 can be factored as:

a) (x + 1)(x + 2) = 0

b) (x – 1)(x – 2) = 0

c) (x + 1)(x – 2) = 0

d) (x – 1)(x + 2) = 0

Answer: b) (x – 1)(x – 2) = 0

Explanation: To factorize x^2 – 3x + 2 = 0, we need to find two numbers whose product is 2 and sum is -3. These numbers are -1 and -2. Therefore, x^2 – 3x + 2 = (x – 1)(x – 2) = 0.

12 . The equation x^2 + 3x + 2 = 0 can be factored as:

a) (x + 1)(x + 2) = 0

b) (x – 1)(x – 2) = 0

c) (x + 1)(x – 2) = 0

d) (x – 1)(x + 2) = 0

Answer: d) (x – 1)(x + 2) = 0

Explanation: To factorize x^2 + 3x + 2 = 0, we need to find two numbers whose product is 2 and sum is 3. These numbers are 1 and 2. Therefore, x^2 + 3x + 2 = (x + 2)(x + 1) = 0.

13 . The equation 2x^2 – 5x + 2 = 0 can be factored as:

a) (2x – 1)(x – 2) = 0

b) (2x + 1)(x – 2) = 0

c) (2x – 1)(x + 2) = 0

d) (2x + 1)(x + 2) = 0

Answer: a) (2x – 1)(x – 2) = 0

Explanation: To factorize 2x^2 – 5x + 2 = 0, we need to find two numbers whose product is 4 and sum is -5/2. These numbers are -1/2 and -4. Therefore, 2x^2 – 5x + 2 = (2x – 1)(x – 2) = 0.

14 . The equation x^2 – 4 = 0 has roots:

a) 2, -2

b) 4, -4

c) 2i, -2i

d) 4i, -4i

Answer: a) 2, -2

Explanation: To solve x^2 – 4 = 0, we can factorize it as (x – 2)(x + 2) = 0. Therefore, the roots are x = 2 and x = -2.

15 . The sum of the roots of the equation x^2 + 5x + 6 = 0 is:

a) 5

b) -5

c) -6

d) -1

Answer: b) -5

Explanation: By Vieta’s formulas, the sum of the roots of a quadratic equation ax^2 + bx + c = 0 is given by -b/a. Therefore, the sum of the roots of x^2 + 5x + 6 = 0 is -5.

16 . The product of the roots of the equation x^2 – 6x + 8 = 0 is:

a) 2

b) 4

c) 8

d) 16

Answer: b) 4

Explanation: By Vieta’s formulas, the product of the roots of a quadratic equation ax^2 + bx + c = 0 is given by c/a. Therefore, the product of the roots of x^2 – 6x + 8 = 0 is 8/1 = 8, which is option c. However, the question asks for the product of the roots, which is the same as the constant term divided by the coefficient of x^2, which is 8/1 = 8. Therefore, the answer is option b.

17 . The roots of the equation x^2 – 4x + 4 = 0 are:

a) 2i, -2i

b) 2, 2

c) 4, -4

d) 1, -1

Answer: b) 2, 2

Explanation: The equation x^2 – 4x + 4 = 0 can be factored as (x – 2)^2 = 0. Therefore, the only root of the equation is x = 2, which is a repeated root.

18 . The roots of the equation x^2 + 3x – 4 = 0 are:

a) 1, -4

b) 1, 4

c) -1, 4

d) -1, -4

Answer: c) -1, 4

Explanation: To solve x^2 + 3x – 4 = 0, we can use the quadratic formula: x = (-b ± sqrt(b^2 – 4ac))/2a. Substituting a = 1, b = 3, and c = -4, we get x = (-3 ± sqrt(9 + 16))/2 = (-3 ± 5)/2. Therefore, the roots of the equation are x = -1 and x = 4.

19 . The roots of the equation 3x^2 – 7x + 2 = 0 are:

a) 1/3, 2

b) 2/3, 1

c) 1/2, 2/3

d) 2/3, 3/2

Answer: a) 1/3, 2

Explanation: To solve 3x^2 – 7x + 2 = 0, we can use the quadratic formula: x = (-b ± sqrt(b^2 – 4ac))/2a. Substituting a = 3, b = -7, and c = 2, we get x = (7 ± sqrt(49 – 24))/6 = (7 ± 5)/6. Therefore, the roots of the equation are x = 1/3 and x = 2.

20 . The roots of the equation x^2 – 2x + 1 = 0 are:

a) 1, 1

b) 0, 1

c) -1, -1

d) None of the above

Answer: a) 1, 1

Explanation: The equation x^2 – 2x + 1 = 0 can be factored as (x – 1)^2 = 0. Therefore, the only root of the equation is x = 1, which is a repeated root.

21 . The roots of the equation 2x^2 – 5x – 3 = 0 are:

a) -3/2, 1

b) -1/2, 3

c) -1/2, -3

d) 1/2, 3

Answer: b) -1/2, 3

Explanation: To solve 2x^2 – 5x – 3 = 0, we can use the quadratic formula: x = (-b ± sqrt(b^2 – 4ac))/2a. Substituting a = 2, b = -5, and c = -3, we get x = (5 ± sqrt(25 + 24))/4 = (5 ± 7)/4. Therefore, the roots of the equation are x = -1/2 and x = 3.

22 . The roots of the equation 2x^2 + 3x – 2 = 0 are:

a) -1/2, 2

b) -2, 1/2

c) -1/2, -1

d) 1/2, 2

Answer: a) -1/2, 2

Explanation: To solve 2x^2 + 3x – 2 = 0, we can use the quadratic formula: x = (-b ± sqrt(b^2 – 4ac))/2a. Substituting a = 2, b = 3, and c = -2, we get x = (-3 ± sqrt(9 + 16))/4 = (-3 ± 5)/4. Therefore, the roots of the equation are x = -1/2 and x = 2.

23 . The roots of the equation x^2 – 7x + 10 = 0 are:

a) 2, 5

b) 5, -2

c) -2, -5

d) -5, 2

Answer: a) 2, 5

Explanation: To solve x^2 – 7x + 10 = 0, we can factorize it as (x – 2)(x – 5) = 0. Therefore, the roots are x = 2 and x = 5.

24 . The roots of the equation 3x^2 + 5x + 2 = 0 are:

a) -1/3, -2

b) -2, -1/3

c) -1/2, -3

d) -3, -1/2

Answer: a) -1/3, -2

Explanation: To solve 3x^2 + 5x + 2 = 0, we can factorize it as (3x + 2)(x + 1) = 0. Therefore, the roots are x = -2/3 and x = -1.

25 . The roots of the equation x^2 + 4x – 12 = 0 are:

a) -6, 2

b) -2, 6

c) -3, 4

d) 4, -3

Answer: a) -6, 2

Explanation: To solve x^2 + 4x – 12 = 0, we can factorize it as (x – 2)(x + 6) = 0. Therefore, the roots are x = 2 and x = -6.

26 . The roots of the equation 2x^2 – 7x + 3 = 0 are:

a) 1/2, 3

b) 3, 1/2

c) 1/3, 2

d) 2, 1/3

Answer: a) 1/2, 3

Explanation: To solve 2x^2 – 7x + 3 = 0, we can factorize it as (2x – 1)(x – 3) = 0. Therefore, the roots are x = 1/2 and x = 3.

27 . The roots of the equation x^2 + 3x + 2 = 0 are:

a) -2, -1

b) -1, -2

c) 1, 2

d) 2, 1

Answer: b) -1, -2

Explanation: To solve x^2 + 3x + 2 = 0, we can factorize it as (x + 1)(x + 2) = 0. Therefore, the roots are x = -1 and x = -2.

28 . The roots of the equation x^2 – 6x + 9 = 0 are:

a) 3, 3

b) 3, -3

c) -3, -3

d) None of the above

Answer: a) 3, 3

Explanation: The equation x^2 – 6x + 9 = 0 can be factored as (x – 3)^2 = 0. Therefore, the only root of the equation is x = 3, which is a repeated root.

29 . The roots of the equation x^2 – 4x – 5 = 0 are:

a) 1, -5

b) -1, 5

c) -1, -5

d) 1, 5

Answer: b) -1, 5

Explanation: To solve x^2 – 4x – 5 = 0, we can factorize it as (x – 5)(x + 1) = 0. Therefore, the roots are x = -1 and x = 5.

30 . The roots of the equation 2x^2 + 7x + 3 = 0 are:

a) -1/2, -3

b) -3, -1/2

c) -1, -3/2

d) -3/2, -1

Answer: a) -1/2, -3

Explanation: To solve 2x^2 + 7x + 3 = 0, we can factorize it as (2x + 1)(x + 3) = 0. Therefore, the roots are x = -1/2 and x = -3.

31 . The roots of the equation x^2 – 5x + 4 = 0 are:

a) 4, 1

b) 1, 4

c) 1, -4

d) -1, -4

Answer: b) 1, 4

Explanation: To solve x^2 – 5x + 4 = 0, we can factorize it as (x – 1)(x – 4) = 0. Therefore, the roots are x = 1 and x = 4.

32 . The roots of the equation x^2 – 7x + 12 = 0 are:

a) 3, 4

b) 4, 3

c) 2, 5

d) 5, 2

Answer: a) 3, 4

Explanation: To solve x^2 – 7x + 12 = 0, we can factorize it as (x – 3)(x – 4) = 0. Therefore, the roots are x = 3 and x = 4.

33 . The roots of the equation x^2 – 3x – 40 = 0 are:

a) -8, 5

b) 5, -8

c) -5, 8

d) 8, -5

Answer: a) -8, 5

Explanation: To solve x^2 – 3x – 40 = 0, we can factorize it as (x – 8)(x + 5) = 0. Therefore, the roots are x = -5 and x = 8.

34 . The roots of the equation 2x^2 + 5x – 3 = 0 are:

a) 1/2, -3

b) -3, 1/2

c) 1, -3/2

d) -3/2, 1

Answer: a) 1/2, -3

Explanation: To solve 2x^2 + 5x – 3 = 0, we can factorize it as (2x – 1)(x + 3) = 0. Therefore, the roots are x = 1/2 and x = -3.

35 . The roots of the equation 3x^2 – 2x – 1 = 0 are:

a) 1, -1/3

b) -1/3, 1

c) -1, 1/3

d) 1/3, -1

Answer: b) -1/3, 1

Explanation: To solve 3x^2 – 2x – 1 = 0, we can use the quadratic formula: x = (-b ± sqrt(b^2 – 4ac)) / 2a. Substituting the given values, we get:

x = (2 ± sqrt(2^2 – 4(3)(-1))) / 2(3)

x = (2 ± sqrt(16)) / 6

x = (2 ± 4) / 6

Therefore, the roots are x = -1/3 and x = 1.

36 . The roots of the equation x^2 + 4x + 4 = 0 are:

a) -2, -2

b) -4, 1

c) 2, 2

d) -2, 0

Answer: a) -2, -2

Explanation: To solve x^2 + 4x + 4 = 0, we can factorize it as (x + 2)(x + 2) = 0. Therefore, the roots are x = -2 and x = -2.

37 . The roots of the equation 2x^2 – 5x – 12 = 0 are:

a) 3/2, -4

b) -4, 3/2

c) 2, -3/2

d) -3/2, 2

Answer: a) 3/2, -4

Explanation: To solve 2x^2 – 5x – 12 = 0, we can factorize it as (2x + 3)(x – 4) = 0. Therefore, the roots are x = 3/2 and x = -4.

38 . The roots of the equation x^2 + x – 12 = 0 are:

a) 3, -4

b) -4, 3

c) 2, -6

d) -6, 2

Answer: b) -4, 3

Explanation: To solve x^2 + x – 12 = 0, we can factorize it as (x – 3)(x + 4) = 0. Therefore, the roots are x = 3 and x = -4.

39 . The roots of the equation x^2 – 3x – 10 = 0 are:

a) 5, -2

b) -2, 5

c) 2, -5

d) -5, 2

Answer: a) 5, -2

Explanation: To solve x^2 – 3x – 10 = 0, we can factorize it as (x – 5)(x + 2) = 0. Therefore, the roots are x = 5 and x = -2.

40 . The roots of the equation 2x^2 – 3x – 2 = 0 are:

a) 2, -1/2

b) -1/2, 2

c) -2, 1/2

d) 1/2, -2

Answer: a) 2, -1/2

Explanation: To solve 2x^2 – 3x – 2 = 0, we can use the quadratic formula: x = (-b ± sqrt(b^2 – 4ac)) / 2a. Substituting the given values, we get:

x = (3 ± sqrt(3^2 – 4(2)(-2))) / 2(2)

x = (3 ± sqrt(25)) / 4

x = (3 ± 5) / 4

Therefore, the roots are x = 2 and x = -1/2.

41 . The roots of the equation x^2 – 6x + 5 = 0 are:

a) 5, 1

b) 1, 5

c) -1, -5

d) -5, -1

Answer: b) 1, 5

Explanation: To solve x^2 – 6x + 5 = 0, we can factorize it as (x – 1)(x – 5) = 0. Therefore, the roots are x = 1 and x = 5.

42 . The roots of the equation x^2 + 2x – 24 = 0 are:

a) 6, -4

b) -6, 4

c) 4, -6

d) -4, 6

Answer: a) 6, -4

Explanation: To solve x^2 + 2x – 24 = 0, we can factorize it as (x + 6)(x – 4) = 0. Therefore, the roots are x = -6 and x = 4.

43 . The roots of the equation 2x^2 + 3x – 2 = 0 are:

a) 1/2, -2

b) -2, 1/2

c) 2, -1/2

d) -1/2, 2

Answer: c) 2, -1/2

Explanation: To solve 2x^2 + 3x – 2 = 0, we can use the quadratic formula: x = (-b ± sqrt(b^2 – 4ac)) / 2a. Substituting the given values, we get:

x = (-3 ± sqrt(3^2 – 4(2)(-2))) / 2(2)

x = (-3 ± sqrt(25)) / 4

x = (-3 ± 5) / 4

Therefore, the roots are x = 2 and x = -1/2.

44 . The roots of the equation x^2 + 7x + 12 = 0 are:

a) -4, -3

b) -3, -4

c) -1, -12

d) -12, -1

Answer: a) -4, -3

Explanation: To solve x^2 + 7x + 12 = 0, we can factorize it as (x + 3)(x + 4) = 0. Therefore, the roots are x = -3 and x = -4.

45 . The roots of the equation 3x^2 – 2x – 1 = 0 are:

a) 1/3, -1

b) -1, 1/3

c) 1, -1/3

d) -1/3, 1

Answer: a) 1/3, -1

Explanation: To solve 3x^2 – 2x – 1 = 0, we can use the quadratic formula: x = (-b ± sqrt(b^2 – 4ac)) / 2a. Substituting the given values, we get:

x = (2 ± sqrt(2^2 – 4(3)(-1))) / 2(3)

x = (2 ± sqrt(28)) / 6

x = (2 ± 2sqrt(7)) / 6

Therefore, the roots are x = 1/3 and x = -1.

46 . The roots of the equation 5x^2 – 6x – 1 = 0 are:

a) -1/5, 1

b) 1, -1/5

c) 1/5, -1

d) -1, 1/5

Answer: a) -1/5, 1

Explanation: To solve 5x^2 – 6x – 1 = 0, we can use the quadratic formula: x = (-b ± sqrt(b^2 – 4ac)) / 2a. Substituting the given values, we get:

x = (6 ± sqrt(6^2 – 4(5)(-1))) / 2(5)

x = (6 ± sqrt(76)) / 10

x = (6 ± 2sqrt(19)) / 10

x = (3 ± sqrt(19)) / 5

Therefore, the roots are x = -1/5 and x = 1.

47 . The roots of the equation x^2 – 2x – 15 = 0 are:

a) 5, -3

b) -5, 3

c) 3, -5

d) -3, 5

Answer: a) 5, -3

Explanation: To solve x^2 – 2x – 15 = 0, we can factorize it as (x – 5)(x + 3) = 0. Therefore, the roots are x = 5 and x = -3.

48 . The roots of the equation 4x^2 – 5x – 1 = 0 are:

a) 1/4, -1

b) -1, 1/4

c) 1, -1/4

d) -1/4, 1

Answer: b) -1, 1/4

Explanation: To solve 4x^2 – 5x – 1 = 0, we can use the quadratic formula: x = (-b ± sqrt(b^2 – 4ac)) / 2a. Substituting the given values, we get:

x = (5 ± sqrt(5^2 – 4(4)(-1))) / 2(4)

x = (5 ± sqrt(41)) / 8

Therefore, the roots are x = -1 and x = 1/4.

49 . The roots of the equation x^2 + 3x + 2 = 0 are:

a) -2, -1

b) -1, -2

c) -1, -1

d) -2, -2

Answer: a) -2, -1

Explanation: To solve x^2 + 3x + 2 = 0, we can factorize it as (x + 2)(x + 1) = 0. Therefore, the roots are x = -2 and x = -1.

50 . The roots of the equation 3x^2 – 7x + 2 = 0 are:

a) 1/3, 2

b) 2, 1/3

c) 1/2, 3

d) 3, 1/2

Answer: a) 1/3, 2

Explanation: To solve 3x^2 – 7x + 2 = 0, we can use the quadratic formula: x = (-b ± sqrt(b^2 – 4ac)) / 2a. Substituting the given values, we get:

x = (7 ± sqrt(7^2 – 4(3)(2))) / 2(3)

x = (7 ± sqrt(37)) / 6

Therefore, the roots are x = 1/3 and x = 2.

51 . The roots of the equation x^2 – 3x – 10 = 0 are:

a) 5, -2

b) -5, 2

c) 2, -5

d) -2, 5

Answer: c) 2, -5

Explanation: To solve x^2 – 3x – 10 = 0, we can factorize it as (x – 5)(x + 2) = 0. Therefore, the roots are x = 5 and x = -2.

52 . The roots of the equation 2x^2 + 7x – 15 = 0 are:

a) 1/2, -15

b) -15, 1/2

c) 5, -3/2

d) -3/2, 5

Answer: c) 5, -3/2

Explanation: To solve 2x^2 + 7x – 15 = 0, we can use the quadratic formula: x = (-b ± sqrt(b^2 – 4ac)) / 2a. Substituting the given values, we get:

x = (-7 ± sqrt(7^2 – 4(2)(-15))) / 2(2)

x= (-7 ± sqrt(169)) / 4

x = (-7 ± 13) / 4

Therefore, the roots are x = 5 and x = -3/2.

53 . The roots of the equation 2x^2 – 5x – 3 = 0 are:

a) -1/2, 3

b) 3, -1/2

c) 1/3, -2

d) -2, 1/3

Answer: a) -1/2, 3

Explanation: To solve 2x^2 – 5x – 3 = 0, we can use the quadratic formula: x = (-b ± sqrt(b^2 – 4ac)) / 2a. Substituting the given values, we get:

x = (5 ± sqrt(5^2 – 4(2)(-3))) / 2(2)

x = (5 ± sqrt(49)) / 4

Therefore, the roots are x = -1/2 and x = 3.

54 . The roots of the equation x^2 + 6x + 8 = 0 are:

a) -2, -4

b) -4, -2

c) -2, -2

d) -4, -4

Answer: a) -2, -4

Explanation: To solve x^2 + 6x + 8 = 0, we can factorize it as (x + 2)(x + 4) = 0. Therefore, the roots are x = -2 and x = -4.

55 . The roots of the equation 3x^2 + 5x + 2 = 0 are:

a) -1/3, -2

b) -2, -1/3

c) -1/2, -3

d) -3, -1/2

Answer: b) -2, -1/3

Explanation: To solve 3x^2 + 5x + 2 = 0, we can factorize it as (3x + 2)(x + 1) = 0. Therefore, the roots are x = -2/3 and x = -1.

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