Question

Mulitply the polynomials
[(x+y)-8]^2

Answer 1

you remember \[(a-b)^2=a^2-2ab+b^2\]
so now
[(x+y)-8]^2=(x+y)^2-2(x+y)(8)+64)
=x^2+2xy+y^2-16(x+y)+64
=x^2+2xy+y^2-16x-16y+64