1.(-2/3x-3/2y)² 2.x²-(x+2)(x-2)-(x+x/1)² 3.[(x+y)²-(x-y)²]/(2xy)4.3x-12x³ 5.-2a³+12a²-18a 6.9a²(x-y)+4b²(y-x) 7.(x+y)²+2(x+y)+1