Here's the question you clicked on:
suzukirider140
Choose the correct simplification of (5x3 − 5x − 8) + (2x3 + 4x + 2). A. 7x3 + x + 6 B. 3x3 − 9x − 10 C. 3x3 + 9x + 10 D. 7x3 − x − 6
just add the ones with equal exponentials.
it will turn out to be D.
Do what @nickymarden says and combine the like terms. Check for yourself but I think its D as well:)