Question

if x + 2 is a factor of 3x² minus 4 kx- 4 k² then find the value of k​

Answer 1

Answer:

f(x)=3x^2-4kx-4k^2

x+2 is factor of f(x)

so putting x=-2

f(-2)=0

3(-2)^2-4k(-2)-4k^2=0

12+8k-4k^2=0

4k^2-8k-12=0

k^2-2k-3=0

k^2-3k+k-3=0

k(k-3)+1(k-3)=0

(k-3)(k+1)=0

k=3,-1