# How do you know if #49x^2 − 28x + 16# is a perfect square trinomial and how do you factor it?

##### 1 Answer

Jun 8, 2015

I usually try to calculate the

You can calculate it using the formula

So in this case you have

So you can't even factor this trinomial.

*To sum up the concept:*

#Delta_x<0 -> # not factorizable#Delta_x=0 -> # perfect square (writable as#(x-a)^2# )#Delta_x>0 -> # factorizable in the form#(x-a)(x-b)#