To find the first and last terms of the expression \((12x^5 + 4x^4 + 9x^3 - 10x^2 + 15) - (24x^5 + 9x^3 - 7x^2 + 8)\), we first need to simplify the expression.
Distributing the negative sign to the second part of the expression:
\[ (12x^5 + 4x^4 + 9x^3 - 10x^2 + 15) - (24x^5 + 9x^3 - 7x^2 + 8) \]
This becomes:
\[ 12x^5 + 4x^4 + 9x^3 - 10x^2 + 15 - 24x^5 - 9x^3 + 7x^2 - 8 \]
Now, combine like terms:
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For \(x^5\): \[ 12x^5 - 24x^5 = -12x^5 \]
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For \(x^4\): \[ 4x^4 \quad \text{(no like terms)} \]
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For \(x^3\): \[ 9x^3 - 9x^3 = 0 \]
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For \(x^2\): \[ -10x^2 + 7x^2 = -3x^2 \]
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For the constant terms: \[ 15 - 8 = 7 \]
Putting it all together, the simplified expression is:
\[ -12x^5 + 4x^4 - 3x^2 + 7 \]
Now, we can identify the first and last terms:
- The first term is \(-12x^5\).
- The last term is \(7\).
Thus, the correct response is:
The first term is −12x^5, and the last term is 7.