Find the values of k for which (k + 4)x^2 + (k + 1)x = -1 has equal roots.
(k + 4)x^2 + (k + 1)x = -1
(k + 4)x^2 + (k + 1)x +1= 0 must have discriminant =0
b^2-4ac = 0
(k+1)^2 - 4 ((k+4)(1)) = 0
k^2 + 2k+1 - 4k-16 =0
k^2-2k-15 = 0
(k-5)(k+3) = 0 k = 5 or -3