求未知数x 3×x=1/10 x×9=12/13 21×x=70/33 22x=33/45 5x=4/15 7x=28/7
问题描述：
求未知数x 3×x=1/10 x×9=12/13 21×x=70/33 22x=33/45 5x=4/15 7x=28/7
答
3×x=1/10 x=1/10×1/3=1/30x×9=12/13 x=12/13×1/9=4/3921×x=70/33 x=70/33×1/21=70/69322x=33/45 x=33/45×1/22=1/305x=4/15 x=4/15×1/5=4/757x=28/7 x=28/7×1/7=4/7