How do you factor squares of binomials?

You should factor a2 - 9 and 4a2 - 4a + 1 by using certain algebraic properties listed below. First: (x + y)(x - y)=x2 - y2 Second: (x - y)(x - y)=x2 - 2xy + y2 So to factor a2 - 9 you use the first property to determine it is (a + 3)(a - 3). To factor 4a2

• 4a + 1 you use the second property to get (2a - 1)(2a - 1).