x²y－3xy²+2yx²－y²x,急用!

3xy+xy+2x²y+yx²+3x²y等于多少 x²-3xy-3x²y²+2yx²-y²x 合并同类项 .先化简,后计算.[2x(x²y-xy²)+xy(xy-x²)]/x²yx=20 6x²y+2xy-3x²y²-7x-5yx-4y²x²-6x² 求6x²y+2xy-3x²y²-7x-5yx-4y²x²-6x 化简、、、最好有过程x²y-3xy²+2yx²-y²x2、（3a²-a 3X²y-3y²X+2Xy²-2yX²当y=-2,X=3时. 7x²y-2xy²+2yx²+y²x-3xy²怎么做?是合并同类项在算 一道初一合并同类项题 2x²y-2y²x+2xy²+2yx² (x³-2xy²)dy+(2y³-3yx²)dx=0求通解 已知x²y²-8xy+4x²+y²+4=0,求y-2x+（yx/2）的2013次 已知x-y=4xy，则2x+3xy-2yx-2xy-y