Quadratic Equations

J&K Bank PO · Quantitative Aptitude · 60 practice questions with answers and explanations: 37 Easy, 23 Medium, 0 Hard.

Sample questions

Sample Easy question 1

What is the larger root of the equation x² − 7x − 8 = 0?

  1. 8
  2. 9
  3. −1
  4. −8
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Answer: A. Factorising gives (x + 1)(x − 8) = 0, so x = −1 or 8; the larger root is 8.

Sample Easy question 2

What is the sum of the roots of x² + 8x + 7 = 0?

  1. 7
  2. −7
  3. −8
  4. 8
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Answer: C. For x² + bx + c = 0 the sum of the roots is −b = −8.

Sample Easy question 3

Solve both equations and give the relationship between x and y. I. x² + 9x + 8 = 0 II. y² + 9y + 8 = 0

  1. x > y
  2. x ≥ y
  3. x = y or the relationship cannot be established
  4. x < y
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Answer: C. Roots of I: x = −1 and −8. Roots of II: y = −8 and −1. Comparing the roots, the relationship is: x = y or the relationship cannot be established.

Sample Medium question 4

What is the product of the roots of x² + 7x = 0?

  1. 2
  2. 1
  3. −7
  4. 0
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Answer: D. For x² + bx + c = 0 the product of the roots is c = 0.

Sample Medium question 5

Solve both equations and give the relationship between x and y. I. x² + 4x − 45 = 0 II. y² − 49 = 0

  1. x > y
  2. x ≥ y
  3. x < y
  4. x = y or the relationship cannot be established
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Answer: D. Roots of I: x = −9 and 5. Roots of II: y = 7 and −7. Comparing the roots, the relationship is: x = y or the relationship cannot be established.

Sample Medium question 6

What is the larger root of the equation x² + 2x − 48 = 0?

  1. −6
  2. −8
  3. 6
  4. 7
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Answer: C. Factorising gives (x − 6)(x + 8) = 0, so x = 6 or −8; the larger root is 6.

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