若3x=7y,则（x+3y):(x-3y)=

若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 若3x=7y,则y比x= ,x:（x+y）= 若x,y为正整数,且满足3x(x+y)-y(x+y)=7,求x,y 若2x=3y,则(x*x+y*y)/x*x=? 若x:y=3则x:(x+y)= 若3x=5y,则x:y=________,(x-y):y=______ 若3x=7y,则（x+3y):(x-3y)= 若x+3y=3x+2y=7,则x+y=几? 若X/Y=7/5,则Y-X/X+3Y= (3x-y)(3y+x)-(x-y)(x+y) 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 （x+y-5)*（x+y-5)+（x-y+3)=0 x*x-y*y 已知:3x-5y=0,求x/y,x-y/y,x-y/x (x+y)/y=8/3则x/y=__ y/x-y=___ (x+y)/y=8/3则x/y=__ y/x-y=___ 若7x+6(x-y)=-4,3x-4(y-x)=18,则x-y=__ 若x+y=3 x²-y² 则x-y=?若x+y=3 x²-y²=24 则x-y=? 推倒公式:(x+y)(x*x-3x+y*y)=x*x*x+y*y*y怎么做.