Final answer:
First simplify both expressions. Then subtract the first expression from the second to get the final answer, 8x^2 - 18.
Step-by-step explanation:
To solve this problem, we first simplify both the components.
The expression 3x^2 - 2x^2 + 3 simplifies to x^2 + 3. Similarly, the expression 5x^2 + 4x^2 -15 simplifies to 9x^2 - 15. After that, we subtract x^2 + 3 from 9x^2 - 15.
This subtraction will lead us to the answer 8x^2 - 18.
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