Answer:
3x3 + 5x2 + 9x - 14
Step-by-step explanation:
(x3 + 4x2 + 12x − 13) − (-2x3 − x2 + 3x + 1)
= (x3 + 4x2 + 12x − 13) + (2x3 + x2 - 3x - 1) distribute the -1
= (x3 + 2x3) + (4x2 + x2) + (12x - 3x) + (-13 - 1) rearrange the terms
= 3x3 + 5x2 + 9x - 14 combine like terms
