1) 9b + 6b - 15 = 615 2) 17x - x + 5x-19 = 170 3) (x - 23) : 26 = 8 4) 1728 : (56-x) = 36

Решим первый пример

1) 9b + 6b - 15 = 615;

15b = 615 - 15;

15b = 600;

b = 600 / 15 = 40.

2) 17x - x + 5x-19 = 170;

21 х = 189;

x = 9.

3) (x - 23) / 26 = 8;

х-23 = 8 * 26;

x - 23 = 208;

x = 208 + 23 = 231.

4) 1728 / (56-x) = 36;

(56 - x) = 1728 / 36;

56 - x = 48;

x = 56 - 48;

x = 8.