(2x-3y)/4+2(x+2y)/5=1 3(2x-3y)/4-(x+2y)/5=﹣4 加减消元法

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 (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 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 (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuaihuajian x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 3X=5Y （X+Y)*3X=(2Y+X)*4+2*2 x+y/2+x-y/6=5 2(x+y)-3(x-y)=-2 (2x-y)(3x-4y)-2(x-y)(2x-5y)简便运算 5/4(x+y)(-x-y)^3*[-4/3(x-y)]*[-3/5(y-x)^2] （x+y）/2- x-y/2=6 3(x+y)=4(x-y) x+y/3+x-y/2=6 4(x+y)-2(x-y)=40 2（x+y)-3(x-y)=3 ,4(x+y)+3(x-y)=15 5x^3y(x-y)^3-10x^4y^3(y-x)^2因式分解