Question

 if x = 3 is one root of the quadratic equation x² - 2kx-6 = 0 ,then find the value of k.

Answer 1

Let  p(x) = x ² - 2kx - 6 = 0

x =  3 is one root of the quadratic equation

 Remainder =  p(3) =  0

p(3)  = 0

(3)² - 2k(3) - 6 = 0

- 6k  = -3

 k = 3/6  = 1 /2

k = 1 / 2