可以这样做:首先8/17 ÷ 7/5 =8/17 x 5/7算式就变成了为:8/17 x 5/7 +5/7 x 9/17 =5/7 x (8/17+9/17) =5/7 x 1 =5/7希望能帮到你
8/17÷7/5+5/7×9/17=8/17×5/7+5/7×9/17=5/7×(8/17+9/17)=5/7×1=5/7