Question

(X-2y)(2y-x) =¿¿??????????

Answer 1

(х-2y)(2y-x) = -(2y-x)(2y-x) = -(2y-x)² = -(4у²-4ху+х²) = -4у²+4ху-х²

Answer 2

(х-2у)(2у-х) =2ху -х²-4у²+2ху= -х²+4ху-4у²= -(х²-4ху +4у²) = -(х-2у)²

или
(х-2у)(2у-х) = (х-2у)  * -1(х-2у) = -(х-2у)(х-2у) = -(х-2у)²