时时彩反水是什么意思:(3x+4y)^2+(2x-y+11)^2=0

（x-y)^3*(x-y)^2*(y-x) 3X(X-Y)+2Y(X-Y) (x+y)2-4(x+y-1) (x-y)^2×(y-x)^3=??? 已知X+Y=-4，求1/2（X+Y)+4(X-Y)-3(X-Y)-3/2(X+Y)-X+Y X^4 +11x^2y^2 +y^2 2y-3x-9x^2+4y^2 45(x-y)^3-30y(x-y)^2 (x^2-y^2)(x^4+x^3y^2+y^4)怎么计算 (x-y)(x^4+x^3y^2+y^4)怎么计算