Найдите число х из пропорции 1) х-5/20=6/7 . 2) 2/7=3/4х . 3) 11/17=22:68х.

1) (х - 5)/20 = 6/7                          2) 2/7 = 3/4х7 * (х - 5) = 20 * 6                          х = 2/7 : 3/4                                                  7х - 35 = 120                                 х = 2/7 * 4/3                               7х = 120 + 35                                х = 8/21                               х = 155 : 7                                     Проверка:х = 155/7                                       2/7 = 3/4 * 8/21                                       х = 22 1/7                                      2/7 = 2/7Проверка:(22 1/7 - 5) : 20 = 6/7120/7 * 1/20 = 6/7                                  3) 11/17 = 22 : 68х                                   11 * 68х = 22 * 17                                   748х = 374                                   х = 374 : 748                                   х = 0,5                                   Проверка:                                   11/17 = 22 : (68 * 0,5)                                   11/17 = 22/34