3(2x-5)-4(3y+4)=5,x+1=5(y+2) x+y=420,30%+40%y=1603(2x-5)-4(3y+4)=5,x+1=5(y+2)x+y=420,30%+40%y=160×80%

3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2 4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11 3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27 先化简再求值(x-y)(x-2y)+(x-2y)(x-3y)-2(x-3y)(x-4y) x=4 y=5 因式分解(x-2y)(x-3y)+(x-4y)(x-5y)+（x-3y)(x-5y)+(x-2y)(x-4y) 化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1 3X=5Y （X+Y)*3X=(2Y+X)*4+2*2 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuaihuajian 5/4(x+y)(-x-y)^3*[-4/3(x-y)]*[-3/5(y-x)^2] （5x+3y)(3y-5x)-(4x-y)(4y+x)= 5x^3y(x-y)^3-10x^4y^3(y-x)^2因式分解 5x^3y(x-y)^3-10x^4y^3(y-x)^2 5X^3Y(X-Y)-10X^4Y^3(Y-X)^2因式分解 (2x-y)(3x-4y)-2(x-y)(2x-5y)简便运算 （x-y）^3×（y-x）^4+（x-y）^2×（y-x）^5 {x+y=1 ,xy=-6{x(2x-3)=0,y=x²-1{(3x+4y-3)(3x+4y+3)=0,3x+2y=5{(x-y+2)(x+y)=0,x²+y²=8{(x+y)((x+y-1)=0,(x-y)(x-y-1)=0 计算(x^8-x^7y+x^5y^3-x^4y^4+x^3y^5-x^y^7+y^8)(x^2+xy+y^2)