Question

упростить выражение (2x-y)*(2x+y)-(2x+y)^2

Answer 1

$(4 x^{2} +2xy-2xy-y^{2})-(4 x^{2} +4xy+y^{2})=4 x^{2} -y^{2}-4 x^{2} -4xy-y^{2}$
$4 x^{2} -y^{2}-4 x^{2} -4xy-y^{2}=-2y^{2}-4xy=2y(y-2x)$