CMA Foundation · Fundamentals of Business Mathematics and Statistics · Quadratic Equations
For the quadratic equation 2x² − 7x + 3 = 0, what is the sum of its roots?
The sum of the roots is 3.5. For a quadratic ax² + bx + c = 0 the sum of roots equals −b/a, which here is 7/2. The roots 3 and 0.5 confirm it. The value 1.5 is the product of roots, not their sum.
- A3.5Correct
- B−3.5
- C1.5
- D−1.5
Explanation
For ax² + bx + c = 0 the sum of roots is −b/a = −(−7)/2 = 3.5. Check: the roots are 3 and 0.5, which add to 3.5. Choosing −3.5 comes from forgetting the sign change in −b/a, and 1.5 is the product c/a.
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