The expansion of a perfect square is
![(a+b)^2 = a^2+2ab+b^2](https://img.qammunity.org/2020/formulas/mathematics/middle-school/8hbyvblnmi5w6s10pwb7fp9ui2b0ev6h84.png)
In words, the square of a sum of two terms is the sum of the squares of the two terms (
and
), plus twice the product of the two terms (
)
So, when determining if you have a perfect square trinomial, you should have two perfect squares. Note that they don't have to be the first and third term, since you can rearrange terms as you prefer.