Answer:
a. 3n + 15
b. 2x + 27
c. 2x + 15
Step-by-step explanation:
a. n + n + n + 15 = 3n + 15
b. 17 + x + x + 10 = 2x + 27
c. 5 + 5 + 5 + 2x = 2x + 15