Question

find K for which
$4x {}^{2} - 2(k + 1)x + k + 4 = 0$
is equal to zero has equal roots

Answer 1

It has equal roots then

b2 - 4ac = 0

b = 2(k+1)

a = 4

c = k + 4

Substituting them we get

2(k+1) - 4×4×(k+4) = 0

K = 33/7.(plus or minus)