Question

When determining if you have a perfect square trinomial, what must the first and third term be?

Answer 1

The expansion of a perfect square is

$(a+b)^2 = a^2+2ab+b^2$

In words, the square of a sum of two terms is the sum of the squares of the two terms ($a^2$ and $b^2$), plus twice the product of the two terms ($2ab$)

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.