3x-5y-6x-7y+9x-2y 能不能帮我把这道合并同类项的题目解一下,教我下是怎么解的

计算(x-y)^7÷(y-x)^6+9-x-y)^3÷(x+y)^2 [2(x-y)^5-8(x-y)^2(x+y)+6y(x-y)^2]÷2(x-y)^2[2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2]÷2(x-y)^2 解方程组2x+y-3z=1,x-2y+z=6,3x-y+2z=9求x,y,z的值解方程组6x+y-z=0,3x-y+z=5,y+2z=4求x,y,z的值 真的实在解不出来,希望你能帮帮忙! 3x+5y-(x+y)=6 2(x+y)-3x=-7 3x+2=y 5x+4=y 7x+6=y 9x+8=y 11x=y 联立方程 有的话 3x+2=y 5x+4=y 7x+6=y 9x+8=y 11x=y 3x+2=y 5X+4=Y 7X+6=Y 9X+8=y 11x=y要如何计算 3x+2=y 5x+4=y 7x+6=y 9x+8=y 11x=y怎么解 y-3x=2,y-5x=4,y-7x=6,y-9x=8,y-11x=0方程组,无 3(x+y)的平方-7(x-y)-9(x+y)的平方-6(x-y) (3x-4y)(5x-4y)-(7x-8y)(6y-5x) 2(2x+3y)(3x+2y)-(6x-y)(2x-5y) 3(x-y)^2-7(x-y)+8(y-x)^2+6(y-x)合并同类项. {6(x-y)-7(x+y)=21 {2(x-y)-5(x+y)=-1 81/8*(-x-y)^6*(x-y)^3*4/9(x+y)^4*(y-x)^2 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 计算：(x-y)^7÷(y-x)^6+(-x-y)^3÷(x+y)^2 2(y-x)的平方-7(x-y)+6(x-y)-3(y-x)的平方