Question

Arătați că x compus cu y=(x+2)(y+2)-2
X•y=xy+2x+2y+2

Answer 1

x o y = xy+2x+2y+2

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

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

Answer 2

$\it x\circ y = xy+2x+2y+2 = xy+2x+2y+4-2 = (xy+2y)+(2x+4) -2=\\ \\ = y(x+2)+2(x+2)-2=(x+2)(y+2)-2$