Answer:
- 12k² + 9k - 10
Explanation:
note that + (-) = -
9k + (- 10) + (- 7k²) + 2k² - 7k²
= 9k - 10 - 7k² + 2k² - 7k² ← collect like terms
= - 12k² + 9k - 10
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