2015 · Q3
For what value of k is (x-5) a factor of x³-3x²+kx-10?
Elementary MathematicsAlgebra
- A-8
- B4
- C2
- D1
Explanation
If (x − 5) is a factor, x = 5 is a root: 5³ − 3·5² + 5k − 10 = 125 − 75 + 5k − 10 = 40 + 5k = 0, so k = −8 (option A).
For what value of k is (x-5) a factor of x³-3x²+kx-10?
Explanation
If (x − 5) is a factor, x = 5 is a root: 5³ − 3·5² + 5k − 10 = 125 − 75 + 5k − 10 = 40 + 5k = 0, so k = −8 (option A).