9-x^3
(a+b)^3
(3x+5y)*(3x-5y)
3x+3y+7x+7y
4x^2+20x+3xy+15y
x^2-4
(2x-3y)^2
a^2+2ab+b^2
x^2+8x+16
(a+x)*(b+x)
c*(a+b)
