x+y=18 x/12 +y/8 =20

x+y=18 x/12 +y/8 =20 12y(x-y)^2-8(x-y)^3=? x+y=180 x/12+y/8=20x+y=180x/12+y/8=20 x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 化简 x / y(x+y) - y / x(x+y) = (x*x+y*y)(x*x+y*y)-(x*x+y*y)=12 求x*x+y*y等于多少 Y-X=45 (85%Y-X)×8=(Y-35-X)×12 Y-X=45 (85%Y-X)×8=(Y-35-X)×12 x(x+y)(x-y)-y(y+x)(y-x)=(x-y)( )填空 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= 已知x^2+y^2-8x+12y+52=0 ,求1/2x-1/x-y(x-y/2x-x^2+y^2) 已知x^2+y^2-8x+12y+52=0 ,求1/2x-1/x-y(x-y/2x-x^2+y^2) x.y都是自然数,且x(x-u)-y(y-x)+12,求x.y得值快1且x(x-y)-y(y-x)=12 12x+20y=20x+12y 12x+20y=20x+15y 解方程 {x+y=20 x-y=12 x+x+x+y=20 x+x+y=14 x=?y=? [x+y=8,x+5y=20] (x+y)/y=8/3则x/y=__ y/x-y=___