2019 · Q48
If p and q are the roots of the equation x² - 15x + r = 0 and p - q = 1, then what is the value of r?
Elementary MathematicsAlgebra
- A55
- B56
- C60
- D64
Explanation
For x^2 − 15x + r = 0, sum of roots p+q = 15 and with p−q = 1 we get p = 8, q = 7. The constant term is the product of the roots, so r = pq = 8×7 = 56.