What is the constant that should be added to the binomial so that it becomes a perfect square trinomial? x^2+8x?

X^2 + 8x

to make this a perfect square trinomial, u will have to have to take half of ur x term, and square it, then add that constant ... so ur x term is 8 ... half of it is 4 ... 4^2 = 16 ... so the constant u need to add is 16

x^2 + 8x + 16 <===

(x + 4) ^2 ... perfect square trinomial

This is what you do-

you would add 16 to make it a perfect square