45 + 15(n − 1) for n = 6

120

Step-by-step explanation:

Plug in what you know so: 45+15(6-1)

So, following the order of operations, you do the parentheses first so: 45+15(5)

Then, still following the order of operations, you'd multiply from left to right. So: 45+75

Then, you add from left to right, so you get 45+75=120

Your answer is 120.