Answer:
16x² - 20x - 6
Step-by-step explanation:
Given
(7x² - 10x - 6) - (- 9x² + 10x)
Distribute both parenthesis noting that the second one is distributed by - 1
= 7x² - 10x - 6 + 9x² - 10x ← collect like terms
= (7x² + 9x²) + (- 10x - 10x) - 6
= 16x² + (- 20x) - 6
= 16x² - 20x - 6
