Question

WHAT TERM SHOULD BE ADDED TO CREATE A PERFECT SQUARE TRINOMIAL?

Answer 1

Answer: We should add the constant 81 to the expression to have a perfect square trinomial.

The perfect square trinomial that would be formed would result from (x + 9)^2.

We can use foil to prove it.

(x + 9)(x + 9)
x^2 + 9x + 9x + 81
x^2 + 18x + 81

81 is the value that must go with 18x in the middle to form the perfect square trinomial.