XY/(100-X)=3/20 , 2XY/(100-2X=2/5 怎么解?
问题描述:
XY/(100-X)=3/20 , 2XY/(100-2X=2/5 怎么解?
答
由一式得 xy=3/20(100-x);
由二式得 xy=1/5(100-2x);
即 3/20(100-x)=1/5(100-2x) 解得x=20
将x=20代入一式解得y=0.6