Selected MCQ

Current Question
If the sum of roots of a quadratic Equation is 6 and product is 8, the Equation is ____.
  • A. x² − 6x + 8 = 0
  • B. x² + 6x + 8 = 0
  • C. x² − 8x + 6 = 0
  • D. x² + 8x + 6 = 0
Correct Answer: A
Explanation:
Equation = x² − (sum)x + product.
Related Question 1
Sum and product of roots of Equation x² + 20x + 3 = 0 are ____.
  • A. 10, 3
  • B. -10, 3
  • C. -20, 3
  • D. -10, -3
Correct Answer: C
Explanation:
Sum = −b/a, product = c/a.
Related Question 2
If Equation is x² − 5x + 6 = 0, product of roots is ____.
  • A. 5
  • B. 6
  • C. −5
  • D. −6
Correct Answer: B
Explanation:
Product = c/a = 6.
Related Question 3
If the sum of roots is −4 and product is 3, the Equation is ____.
  • A. x² + 4x + 3 = 0
  • B. x² − 4x + 3 = 0
  • C. x² + 3x + 4 = 0
  • D. x² − 3x + 4 = 0
Correct Answer: A
Explanation:
Substitute into standard form.
Related Question 4
If the roots of a quadratic Equation are 20 and −7, what is the Equation?
  • A. x² + 13x − 140 = 0
  • B. x² − 13x + 140 = 0
  • C. x² − 13x − 140 = 0
  • D. x² + 13x + 140 = 0
Correct Answer: C
Explanation:
Sum = 13 and product = −140, so equation is x² − 13x − 140 = 0.
Related Question 5
The roots of Equation 3x² − 12x + 10 = 0 are ____.
  • A. Rational and unequal
  • B. Complex
  • C. Real and equal
  • D. Irrational and unequal
Correct Answer: D
Explanation:
Discriminant >0 but not a perfect square.