What constant k will make y^2 + 24y + 16 + k the square of a binomial?
LOL.
y^2 + 24 y + 144
= (y+12)^2
is a square of binomial.
y^2 + 24y + 144 = y^2 + 24y + 16 + k
16 + k = 144
k = 144 - 16 = 128