Verified answer

4,2p-p=5,12

3,2р=5,12

р=5,12/3,2

р=1,6

Проверка: 4,2*1,6-1,6=5,12

                   6,72-1,6=5,12

                     5,12=5,12

4.2р-р=5.12

3.2р=5.12

р=5.12:3.2

р=1.6

проверка

(4.2*1.6)-1.6=6.72-1.6=5.12