1/3 (3x-6) - 2/7 (7x-21) = 9 решите уравнение

1/3 (3x-6) - 2/7 (7x-21) = 9

х-2-2 х+6=9

-х=9-6+2

х=-5

1/3 * (3 х-6) - 2/7 * (7 х-21) = 9

1) 1/3*3 х = 3 х/3 = х

2) 1/3*6 = 6/3 = 2

3) 2/7*7 х = 2*х = 2 х

4) 2/7*21 = 2*3 = 6

х-2-2 х+6 = 9

-х = 9-6+2

-х = 5

х = - 5

Проверяем:

1/3 * (3 * (-5) - 6) - 2/7 * (7 * (-5) - 21) = 1/3 * (-21) - 2/7 * (-56) = - 7+16 = 9

Ответ: - 5.