（1）x÷0.6=1.72

                 x=1.72×0.6

                 x=1.032（2）6.5x+1.5x=15

                    8x=15

                      x=1.875

（3）0.72×3-7x=0.06

              2.16-7x=0.06

                      7x=2.1

                        x=0.3（4）7x÷3=8.19

              7x=8.19×3

              7x=24.57

                x=3.51

（5）6x-8.4=0

               6x=8.4

                 x=1.4

                 8m=12

                   m=1.5