[(1/9(x+y)^3-2(x+y)^2-2/3(x+y)]÷x+y/3x+y/3x+y是整体..

9y=3x-(x-1),4(x+y)-(2x+4)=8y [(1/9(x+y)^3-2(x+y)^2-2/3(x+y)]÷x+y/3x+y/3x+y是整体.. 9xy(x-y)(x+1)-3y(x-y)(3x+2y)+6y的平方(x-y)(x+1),因式分解 x²/xy-x/y 3x/4x+y - x-2y/4x+y (1-y/y+x)÷x/y²-x² 计算：1.（x-1)^2+2(1-x) 2.(x-y)/(x+3y)÷(x^2-y^2)/(x^2+6xy+9y^2)-2y/(x+y）1.（x-1)^2+2(1-x)2.(x-y)/(x+3y)÷(x^2-y^2)/(x^2+6xy+9y^2)-2y/(x+y） 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 (x-y)/4+(x+y)/5=1/4 (x+y)/9-(x-y)/3=//2(x-y)/4+(x+y)/5=1/4(x+y)/9-(x-y)/3=//2 化简（x+y)+(2x+y/1*2)+(3x+y/2*3)+.+(9x+y/8*9) 化简:（x+y）+(2x+y/1*2)+(3x+y/2*3)+...+(9x+y/8*9) 解方程组 3(x+y)-2(x-y)=9,5(x+y)+2(x-y)=-1 解方程组:{3(x+y)-2(x-y)=9,5(x+y)+2(x-y)=-1} 计算:(x-y)(1/9x-y)-(1/3x-y)(1/3x+y) 解二元一次方程 {3(x+y)-4(x-y)=-9 x+y/2+x-y/6=1 3(x+y)-2(x-y)=11 4(x+y)+3(x-y)=9 4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11 81/8*(-x-y)^6*(x-y)^3*4/9(x+y)^4*(y-x)^2 计算(x-y)^7÷(y-x)^6+9-x-y)^3÷(x+y)^2 (3x-y)^2+(3x+y)(3x-y),x=1,y=-2