Square of a binomial is a factor which the product is perfect square trinomial, to get its product here are some of my examples:
[tex](x+15)^{2}[/tex]
[tex] x^{2} + 2(15)(x)+15^{2}[/tex]
Simplify,
[tex] x^{2} +30x+225[/tex]
Explanation: To get the product you'll just have to square the first term, then 2 multiplied by the product of the first and second term plus the square of the last term.