Question

proof that(X+y-2)² =x²+y²+z²+2xy-2yz​

Answer 1

Answer:

(x+y-z)²

=(x+y) ^2-2*(x+y) *z+z^2

=x^2+2xy+y^2-2xz-2yz+z^2

=x^2+y^2+z^2+2xy-2xz-2yz