Решение:
- a) $$7a + 8a = (7+8)a = 15a$$
- б) $$27c - c = 27c - 1c = (27-1)c = 26c$$
- в) $$59z - z + 73z = 59z - 1z + 73z = (59 - 1 + 73)z = 131z$$
- г) $$16b - 5b = (16-5)b = 11b$$
- д) $$d + 34d = 1d + 34d = (1+34)d = 35d$$
- e) $$38x + 17x - 54x + x = 38x + 17x - 54x + 1x = (38 + 17 - 54 + 1)x = 2x$$
Ответ: a) $$15a$$, б) $$26c$$, в) $$131z$$, г) $$11b$$, д) $$35d$$, е) $$2x$$