1) 6 * m + m - 35 = 21;

Приведем подобные.

7 * m - 35 = 21;

7 * m = 21 + 35;

7 * m = 56;

m = 56/7;

m = 8.

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

31 * n = 134 + 145;

31 * n = 279;

n = 279/31;

n = 9.