求1800/x+1800/y=350 2400/x+1200/y=300 的解是多少

求1800/x+1800/y=350 2400/x+1200/y=300 的解是多少 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) y=2x*arctan(y/x),求y‘’ 已知x-y=3,求[（x+y)(x-y)-(x-y)^2+2y(x-y)]除以的值 已知3x =2y 求x/x+y+y/x-y-y²/x²-y² x+2y=2x+y+1=7x-y 求：2x-y? x^2+y^2=15,x+y=7,x＞y,求x-y 如果|X|=4 |Y|=2 且|X+Y|=X+Y 求X+Y 已知|x|=2,|y|=3,|x+y|=-(x+y)求x-y f(x+y,x-y)=(x^2-y^2)/2xy,求f(x,y)! 求(X+Y)(X-Y)(X²+Y²),X=5 Y=2, y=3(x-y),x=2(x-y)求x,y的值 f(x+y,y/x)=x^2-y^2求f(x,y) 已知x≠y,x^2-x=y^2-y,求x+y的值. f(x+y,y/x)=x^2-y^2,求f(x,y),详见里面 (x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) x,y 满足x(x-2)-y(y-6)=-10,求x,y的值 若x*x+y*y=x+y-1/2,求x,y的值如题