how do you simplify and factor (2a-b)^2-4

Question

We are just learning basic factoring.  

Answer 1

X² - Y² = (X - Y)(X + Y)

 

Let X = 2a-b and Y = 2.

 

Then, (2a-b)² - 4 = (2a-b)² - (2)²

 

                          = (2a-b-2)(2a-b+2)