a)A-(xy+$x^2$-$y^2$)=$\frac{2}{3}$$x^2$+$y^2$
A =$\frac{2}{3}$$x^2$+$y^2$+(xy+$x^2$-$y^2$)
A =($\frac{2}{3}$$x^2$+$x^{2}$)+($y^2$-$y^2$)+xy
A =$\frac{5}{3}$$x^{2}$+xy
b) A+(x2−2y2)=x2−y2+3y2−1A+(x2-2y2)=x2-y2+3y2-1
A =x2−y2+3y2−1−(x2−2y2)A=x2-y2+3y2-1-(x2-2y2)
A =x2−y2+3y2−1−x2+2y2A=x2-y2+3y2-1-x2+2y2
A =(x2−x2)−(y2−2y2+3y2)−1A=(x2-x2)-(y2-2y2+3y2)-1
A =−2y2−1A=-2y2-1
c) (x3y2−xy2+3)−A=2x3y2+4x2y2−xy2−1(x3y2-xy2+3)-A=2x3y2+4x2y2-xy2-1
A=x3y2−xy2+3−2x3y2−4x2y2+xy2+1A=x3y2-xy2+3-2x3y2-4x2y2+xy2+1
A=(x3y2−2x3y2)−(xy2−xy2)+(3+1)−4x2y2A=(x3y2-2x3y2)-(xy2-xy2)+(3+1)-4x2y2
A=−x3y2+4−4x2y2A=-x3y2+4-4x2y2
