若1/X-1/Y=2,求3X+XY+3Y/X-XY-Y的值

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若1/X-1/Y=2,求3X+XY+3Y/X-XY-Y的值若1/X-1/Y=2,求3X+XY+3Y/X-XY-Y的值若1/X-1/Y=2,求3X+XY+3Y/X-XY-Y的值题目错误,分子应该是3X+

若1/X-1/Y=2,求3X+XY+3Y/X-XY-Y的值
若1/X-1/Y=2,求3X+XY+3Y/X-XY-Y的值

若1/X-1/Y=2,求3X+XY+3Y/X-XY-Y的值
题目错误,分子应该是3X+XY-3Y
分子分母同除以XY
分子=(3X+XY-3Y)/XY=3X/XY+XY/XY-3Y/XY=3/Y+1-3/X=-3(1/X-1/Y)+1=-3*2+1=-5
分母=(X-XY-Y)/XY=X/XY-XY/XY-Y/XY=1/Y-1-1/X=-(1/X-1/Y)-1=-2-1=-3
所以原式=(-5)/(-3)=5/3

是(3X+XY+3Y)/(X-XY-Y)还是 3X+XY+3Y/X-XY-Y?