CA Foundation · Quantitative Aptitude · Equations
What is the sum of the roots of the equation 3x² − 12x + 5 = 0?
The sum of the roots of a quadratic ax² + bx + c = 0 equals −b/a. Here a is 3 and b is −12, so the sum is 12/3, which is 4. The figure 5/3 is the product of the roots, not their sum.
- A−4
- B4Correct
- C12
- D5/3
Explanation
For ax² + bx + c = 0 the sum of the roots is −b/a. Here a = 3 and b = −12, so the sum is −(−12)/3 = 4. The value 5/3 is the product of the roots (c/a), not the sum.
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