Question

simplify (algebraic expressions)

Answer 1

$\Huge\Bold\left(x+y\right)\left(x+y+z\right)=x^2+2xy+xz+y^2+yz$

$-(x-y)(x-y-z)=-x^2+2xy+xz-y^2-yz$

$x^2+2xy+xz+y^2+yz-x^2+2xy+xz-y^2-yz$

$x^2-x^2+2xy+xz+2xy+xz+y^2-y^2+yz-yz$

$4xy+2xz+y^2-y^2+yz-yz$

=4xy+2xz