Question

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

Answer 1

3^2 - 2 k 3 - 6=0
9-6k-6=o
3-6k=0
3=6k
k=3/6
k=1/2

Answer 2

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