(x+y)^2=x^2+2xy+y^2
4x^2+12x+9=(2x+3)^2
(x-y)(x+y)=x^2-y^2
x^2-y^2=(x-y)(x+y)
x^3-y^3=(x-y_(x^2+xy+y^2)
(p-g)^2=p^2-2pq+q^2
25a^2+10a+1=(5a+1)^2
(4+y^2)(y^2-4)=y^4-16
25x^2-y2=(5x-y)(5x+y)
(-a-2)^2=a^2+4a+4
m^3-n^3=(m-n)(m^2+mn+n^2)
(9-y)^2=81-18y+y^2
b^2+4a^2-4ab=(4a-b)^2
(9a-b^2)(b^2+9a)=81a^2-b^4
(b+3)^2=b^2+6b+9