{X+X/2=15 {X/2+Y=12怎么解、?{X+X/2=15{X/2+Y=12

x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 (12-x)*y+x*2=26 (15-x)*y+y*2=35(12-x)*y+x*2=26 (15-x)*y+y*2=35 x^2+y^2=15,x+y=7,x＞y,求x-y 2（x+y)-3(x-y)=3 ,4(x+y)+3(x-y)=15 y=x^2-2x（x y=x^2+2x(x 3^x+2x=y,x x^2+xy=12,xy+y^2=15,求(x+y)^2-(x+y)(x-y) 填空：x-y/x+y=( )/x^2-y^2 （x-y)2•(y-x)³(x-y)=? x²-(x-2y)(x+2y)+(x²-y)(y+x²)=? (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= (x+y)(x-y)+(x-y)平方-(x-y)(3x-y) 其中x=-2 y=3分之一 (X,Y) f(x,y)={12y^2,0 12y(x-y)^2-8(x-y)^3=? 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 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)