Answer:
5x² + 5x + 9
Explanation:
(3x + 4) + ((5x² - 1) + (2x + 6))
Remove parenthesis
3x + 4 + 5x² - 1 + 2x + 6
Group like terms
5x² + 3x + 2x + 4 - 1 + 6
Subtract 1 from 4
5x² + 3x + 2x + 3 + 6
Add 3 and 6
5x² + 3x + 2x + 9
Combine like terms
5x² + 5x + 9
Answer: 5x² + 5x + 9