Question

решить тождество x(y-2)+2(x+y)=y(x+2)

Answer 1

xy - 2x + 2x + 2y = yx + 2y;

xy - yx + 2y - 2y = 0;

0 = 0, доказано

Answer 2

x(y-2)+2(x+y)=y(x+2)
x(y-2)+2(x+y)=xy-2x+2x+2y=xy+2y=

=y(x+2)