3(x-3)+10(2/3+y)=13,22(x-3)+5(2/3+y)=27用加减消元法算的过程

(x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuaihuajian (x+y)(x-y)+(x-y)平方-(x-y)(3x-y) 其中x=-2 y=3分之一 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) (x+y)(2x-3y)=? (x+2y)(x-2y)-(2x-y)的平方+(3x-y)(2x-5y)其中x=-1 y=13分之1 3x+x+4y+(90+10)x=3y-(2x+y)+510y=34x {4x-3y-10=0 3x-2y=0,{3x-4(x-y)=2 2x-3y=1,{2(x+y)-(x-y)=3 (x+y)-2(x-y)=1 若x-y不等于0,2x-3y=0,则分式(10x-11y)/(x-y)的值是（）?(10x-11y)/(x-y) =[(8x-8y)+(2x-3y)]/(x-y) =8为什么8X-8Y=8？(10x-11y)/(x-y)=[(8x-8y)+(2x-3y)]/(x-y)=8+(2x-3y)]/(x-y)=8+0=8 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= 已知x-y=3,求[（x+y)(x-y)-(x-y)^2+2y(x-y)]除以的值 已知3x =2y 求x/x+y+y/x-y-y²/x²-y² 2(x+y)-(x-3y)=13 4（x+y）+3（x-3y)=1解方程组 2(x+y)-(x-3y)=13 4（x+y）+3（x-3y)=1 {x=y-3 {x+y=11 {2x+y=13 {3x-2y=81.{x=y-3 {x+y=112.{2x+y=13 {3x-2y=8 x^2+4y^2-6x+4y+10=0,求x^4-y^4/(x+2y)(x-2y)*x+2y/xy^2+y^3除以（x^2+y^2/y)^2的值 2x+4y=10 X*y=3 化简求值：已知x、y满足：x^2+y^2-4x+6y+13=0 求代数式 的值.(3x+y)^2-3(3x-y)(x+y)-(x-3y)(x+3y)急用！ 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值