1) 6m+m-35=21 2) 17n+14n-145=134 3) 5n+9n+32=200

1) 6m + m - 35 = 21;

7m - 35 = 21;

7m = 21 + 35;

7m = 56;

m = 56 : 7;

m = 8.

Проверка:

6 * 8 + 8 - 35 = 21;

48 + 8 - 35 = 21;

56 - 35 = 21;

21 = 21.

Ответ: m = 8.

2) 17n + 14n - 145 = 134;

31n - 145 = 134;

31n = 134 + 145;

31n = 279;

n = 279 : 31;

n = 9.

Проверка:

17 * 9 + 14 * 9 - 145 = 134;

153 + 14 * 9 - 145 = 134;

153 + 126 - 145 = 134;

279 - 145 = 134;

134 = 134.

Ответ: n = 9.

3) 5n + 9n + 32 = 200;

14n + 32 = 200;

14n = 200 - 32;

14n = 168;

n = 168 : 14;

n = 12.

Проверка:

5 * 12 + 9 * 12 + 32 = 200;

60 + 9 * 12 + 32 = 200;

60 + 108 + 32 = 200;

168 + 32 = 200;

200 = 200.

Ответ: n = 12.