3.8+(5/2.5)=3.8+2=5.85.8/5=1.36
解:设这个数为X5X一5÷2.5=3.8 5X一2=3.8 5X=5.8 X=1.16
5x-5/2.5=3.8 5x-2=3.85x=5.8x=5.8/5x=1.16
5x-2.5/5=3.8 x=0.86