1. **State the problem:** Simplify the expression $$9t^2 - 7t + 2 + (3t + 10)$$ and verify if it equals $$2x^2 - 9x - 20$$. 2. **Combine like terms:** Add the polynomials by combining coefficients of the same powers of $t$. 3. Write the expression without parentheses: $$9t^2 - 7t + 2 + 3t + 10$$ 4. Combine like terms: - For $t^2$: only $9t^2$ - For $t$: $-7t + 3t = -4t$ - For constants: $2 + 10 = 12$ 5. The simplified expression is: $$9t^2 - 4t + 12$$ 6. **Compare with the given sum:** The given sum is $$2x^2 - 9x - 20$$ which is different from our simplified expression. 7. **Conclusion:** The sum of the given expressions is $$9t^2 - 4t + 12$$, not $$2x^2 - 9x - 20$$. This shows the given sum is incorrect or refers to a different problem.