若4/x=3/y,求y/x+y的值.

若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 若(x*x+y*y)(x*x+y*y)-4x*x*y*y=0,求代数式(x*x+5xy+y*y)/(x*x+2xy+y*y)的值 若x+y=4,xy=3,求y/x + x/y的值. 若x*x-4y*y=-15,x+2y=3,求x和y的值 已知x-y=1,求[(x+2y)²+(2x+y)(x-4y)-3(x+y)(x-y)]÷y的值 已知x-y=1,求[(x+2y)^2+(2x+y)(x-4y)-3(x+y)(x-y)]除以y的值大神们帮帮忙 x/3=y/4,求(x*x-xy)/(x*x+y*y)的值 已知(x+2y)(2x-3y)=y(y-4x),试求x/y的值 已知x-y=3,求[（x+y)(x-y)-(x-y)^2+2y(x-y)]除以的值 (-x+6):(x-y);(4x+y)=3;14:1,求x+y的值. 若x+y=4,x^3+y^3=(x+y)(x^2-xy+y^2)z,求x^3+12xy+y^3的值. 若x-y=1,求代数式x(x-y)+y(y-x)+2013的值 若x^2-4x+y^2-10y+29=0,求x^2y^2+2x^3y^2+x^4y^2的值 y=3(x-y),x=2(x-y)求x,y的值 已知|3x-y|+|x+y|=0,求x-y除以x*y的值. 若2lg(x-3y)=lgx+lg(4y)求x/y的值 若4/x=3/y,求y/x+y的值. 若4x-3y=0,则求(x+y):y的值