Question

The quadratic equation 4x^2+ KX +3-k =0 has a repeated root.
Find the possible values of k, and the repeated root in each case.

Answer 1

Answer

-4 or -12

Explanation

4x^2+kx + 3-k =0

b^2 = 4 ac

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

k^2 = 16(3-k)

k^2 = 48- 16k

k^2 +16k- 48=0

k^2+ 12k+4k -48=0

k(k+12) +4 (k+12)=0(k+4) (k+12)=0

so the answer is either -4 or -12