(x+2)^2=x^2+4x+4
(x-1)^2=x^2-2x
x^2-9=(x+3)(x-3)
x^2-1=0
2(x+1)=2x+2
3x/x=3
2x+9=2x-11
10x^2=0
3/x=0
2x/3=0
7x-14=0
5x^2+2=0
2x-5=3x+7
