Answer:
Take the square root of the constant (number w/o the variable) and then multiply that by 2.
Step-by-step explanation:
A perfect square trinomial is something like this: If I have 6x, and I want to find the last term I would take half a six and then square it to get 9.
SO.... To get the middle term of a perfect square trinomial, you would need to do the reverse.. So...
1) Take the square root of the constant...
2) Multiply that by 2