Question

For what value of k are the roots of the quadratic equation kx2 – 2 (k + 2) x + (k + 5) = 0 real and equal ?

Answer 1

For the roots to be zero ,
D should be zero
D=0
b²-4ac=0
(-2(k+2))²-4(k)(k+5)=0
4(k+2)²-4k²-20k=0
4k²+16+16k-4k²-20k=0
4k=16
k=4

Therefore k must be equal to 4 for the equation to have equal roots

Hope it helped you!!  :)