perfect square

Perfect squares are number that equals numbers times themselves. e.g. 49 is a perfect square (of 7x7).

x^2 * x^2 = x^4 so x^4 is a perfect square.

Perfect square trinomials

https://study.com/academy/lesson/perfect-square-trinomial-definition-formula-examples.html

binomial (two terms): x+3 trinomial (three terms): x^2+5x-6

perfect square trinomials = value of multiplying a binomial by itself: $3x+2y^2=9x^2+12xy+4y^2$

(x+2)(x+2) = x^2+4x+4

Formula for spotting them: $(a+b{)}^2=a^2+2ab+b^2$