已知1/X+1/Y=6,则3X-2XY+3y/3XY+X+Y=多少

问题描述:

已知1/X+1/Y=6,则3X-2XY+3y/3XY+X+Y=多少

1/X+1/Y=6
两边乘XY
Y+X=6XY
原式=[3(X+Y)-2XY]/[(X+Y)+3XY]
=[3(6XY)-2XY]/[(6XY)+3XY]
=16XY/9XY
=16/9