5x^3y-6x-7x^3y-8x=

(3x-4y)(5x-4y)-(7x-8y)(6y-5x) 5x^3y-6x-7x^3y-8x= 3x+5y-(x+y)=6 2(x+y)-3x=-7 用递归法求y=x-(x*x*x/3!)+(x*x*x*x*x/5!)-(x*x*x*x*x*x*x/7!)+. [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 已知x.x+y.y-6x-8y+25=0,求3x.x+5y的值 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= （x+y-5)*（x+y-5)+（x-y+3)=0 x*x-y*y 已知:3x-5y=0,求x/y,x-y/y,x-y/x x+y=1 5x-2y=8 3x-y=7 2x-y=3x表示y和用y表示x 3(x-y)^2-7(x-y)+8(y-x)^2+6(y-x)合并同类项. 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 x+y/2+x-y/6=5 2(x+y)-3(x-y)=-2 6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5 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