What constant $k$ will make $y^2 + 24y + 16 + k$ the square of a binomial?
y^2 + 24y + 16 + k
Take (1/2) of 24 = 12
Square this = 144
So....this must be added to y^2 + 24y to have a perfect square binomial
Which implies that
144 = 16 + k subtract 16 from both sides
128 = k
+612 
