Using the Discriminant to find the value of 'k'. Find the value(s) of $k$ for which the equation, $(x+2)(x+k)=-1$, has equal roots.
(I cannot get the two values as stated in the answer $k=0$ and $k=4$.
My final line of working doesn't seem to factorize, it is $k^2-4k+8=0$)

the discrimnant is given by $$k^2-4k$$ and we get $$k(k-4)=0$$ if $$k=0$$ or $$k=4$$
