xy^2-x-yx^2+y变为(y-x)(xy+1)xy^2-x-yx^2+y化为(y-x)(xy+1)感觉不像十字相乘法.

xy^2-x-yx^2+y变为(y-x)(xy+1)xy^2-x-yx^2+y化为(y-x)(xy+1)感觉不像十字相乘法. -x^2y+5xy^2-yx^2合并同类项 (xy-x^2)÷x^2-2xy+y^2/xy*x-y/y^2*yx^-2(xy-x^2)÷{x^2-2xy+y^2/xy}*{x-y/y^2}*{yx^-2} 3xy+xy+2x²y+yx²+3x²y等于多少 因式分解x^2+xy+3x+3yx^2+xy+3x+3y 因式分解 x^2y-3xy^2+2yx^2-y^2x化简 X^2Y-3XY^2+2YX^2-Y^2X=? 化简 x²y-3xy²+2yx²-y²x x²y-3xy²+2yx²-y²x x²y－3xy²+2yx²－y²x,急用! x²y-3xy²+2yx²-y²x（列算式） 已知X-Y=4XY,求(2X+3Y-2Y)/(X-2YX-Y)的值 (x^2+yz)/(x^2+x(y-z)-yz)+(y^2-xz)/(y^2+y(x+z)+zx)+(z^2+yx)/(x^2-z(x-y)-yx)最后一项应为：(z^2-xy)/(z^2+z(y-x)-xy) 2x²y+3xy²+5xy-6yx+2 合并同类项 合并同类项 2x的平方y+3xy的平方+5xy-6yx+2 x+y=a,xy=b,xy^2+yx^2=? 已知x-y=6,xy=-1,求(2x+3x-2xy)-(x+4y+xy)-(3yx-2x+2y)的值 已知xy满足x^2+y^2+4/5=2x+y 求代数式yx/x+y的值