1.(8a-2x)-(9a+6x)=8a-2x-9a-6x=-a-8x
2.(x2y + 4x - 3y2)+(8x+3y2-2x2y)+(-2x+y2)=x2y+4x-3y2+8x+3y2-2x2y-2x+y2=-x2y+10x+y2=10x-x2y+y2
3.(4x+8)+(x-15)=2
4x+8+x-15=2
5x-7=2
5x=2+7
5x=9
x=9:5
x=1.8
4.A-D=(2x2y + 4x2 + 5y2x + y2)-(4x2 + y2 + 2x2y + 5y2x)=2x2y + 4x2 + 5y2x + y2 -4x2 - y2 - 2x2y - 5y2x =0
5.16,8x + y2 - (8x2 + 4y - (10y2 - 2x))=16,8x + y2 - (8x2 + 4y -10y2+2x=16,8x + y2 - 8x2 - 4y + 10y2-2x=14.8x+11y2-8x2-4y2