Problem: Square the binomial (x + 6).
Solution: (x + 6)2 = x2 + 12x + 36
x2 is the square of x.
12x is twice the product of x with 6. (x· 6 = 6x. Twice that is 12x.)
36 is the square of 6.
x2 + 12x + 36 is called a perfect square trinomial. It is the square of a binomial.
