（-2x)(2x+1) (-3x+2y)(-3x-2y) (-4x+3y)的平方 (x+2y)(-x-2y)

化简 3x(x^2-x-1)-(x+1)(3x^-x) X^3(x-y)+x(y-x) x(x-y)2-(y-x)3 [2/3x-2/x+y(x+y/3x-x-y)]/x-y/x 化简：{2/3x-2/(x+y)[(x+y)/3x-x-y]}/(x+y)/x 计算2/3x-2/x+y(x+y/3x-x-y)/x-y/x 化简3x-2/(x+y)[(x+y)/3x-x-y]÷(x-y)/x x²/xy-x/y 3x/4x+y - x-2y/4x+y (1-y/y+x)÷x/y²-x² 计算：1-2x+x^2/x-x^3*xy+x^2y/x-x^2 函数,y=3x/(x^2+x+1) ,x 函数y=3x/(x^2+x+1) （x 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 1/(x-y)+1/(x+y)+2x/(x^2+y^2)+4x^3/(x^4+y^4)化简 因式分解x(x+y)(x-y)-x(x+y)^2 因式分解3x^2(x-y)+6x(y-x) (3x-y)^2+(3x+y)(3x-y),x=1,y=-2 二元一次方程 ：2(x+y)-(x-y)=3 (x+y)-2(x-y)=1 (x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) 2(x+y)-3(x-y)=1 6(x+y)+(x-y)=51