The expression "8n 3" appears to be missing an operator between the terms. If you meant "8n + 3," then the answer is simply that expression itself, representing a linear function of n. If you meant something else, please clarify the relationship between the terms.
It is: -3+8n-5 = 8n-8 when simplified
3 + 8n = -58n = -8n = -1
8n-5 = 3
11
11
3+3 is 6
2n x 2n x 2n = 8n^3
11
2.6667
(n - 3)(n - 5) = n² - 8n + 15
8n +3
-((3n - 1)(n + 3))