(2x-3y ) la puterea a 2-a + ( x+6y) la puterea a 2-a

Răspuns :

=(2x)²-2*2x*3y+(3y)²+x²+2*x*6y+(6y)²=4x²-12xy+9y²+x²+12xy+36y²=
=5x²+45y²=5(x²+9y²)