(y-9)^2
(8-a)^2
y^3-0.09
y^3-1
(40+b)^2
(7x-2)(7x+2)
(10x-7y)(10x+7y)

(y-9)^2=y^2-18y+81(8-a)^2=64-16a+a^2y^2-0.09=(y-0,3)(y+0,3)y^3-1=(y-1)(y^2+y+1)(40+b)^2=1600+80b+b^2(7x-2)(7x+2)=49x^2-4(10x-7y)(10x+7y)=100x^2-49y^2