1/x^2+1/y^2-6/x-8/y+25=01/x^2 + 1/y^2 - 6/x - 8/y + 25=0求x+y/xy的值

【2(x-y)(x-y)(x-y)-8(x-y)(x-y)(x+y)+6y(x-y)(x-y)]/2(x-y)(x-y) [(-x-y)(-x+y)-(x+y)^2-x(y-y^2)}÷1/2y 2(x+y)-3(x-y)=1 6(x+y)+(x-y)=51 {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 {6(x-y)-7(x+y)=21 {2(x-y)-5(x+y)=-1 {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 1、(-7x^y)(2x^y-3xy^3+xy) 2、((x-y)^6)/((y-x)^3)/(x-y) 因式分解：-1/2*x*x*x*y+1/4*x*x*y*y-1/8*x*x*x*y*y*y 解方程组8/(x+y) +(x-y)/2=3,6/(x+y)-(x-y)/4=1 2x+3y-1=y-x-8=x+6 ,y=? 计算:1/(x-y)-1/(x+y)-2y/(x^2+y^2)-4y^3/(x^4+y^4)-8x^7/(x^8+y^8) 已知：2x+y=6,x-3y=1 求7y(x-3y)(x-3y)-2(3y-x)(3y-x) (1)x^2*x^8+x^13/x^3 (2)a^19/a^12/a^3 (3) (x-2y)^5/(2y-x)^3 (4)(x-y)^5/(x-y) (5)(x-y)^6/(y-x)^4 1、y-x/x²-y²2、(x-y)(y-z)(z-x)/(z-y)(y-x)(x-z) (x-y)(2x-y-1) (x/x+y-x/y-x-2xy/x.x-y.y)/(1/x-1/y) 分式化简 已知x求^2+y^2-6x-8y+25=0求1/x-y /x+y/x^4-y^4 (x+y)(x-y)+(x-y)^2-(6x^2×y÷2y-2xy^2÷2y)其中x=-3,y=1/3