Question:
Subtract the sum of 2x − x2 + 5 and − 4x − 3 + 7x2 from 5.
Solution:
We have to subtract the sum of $\left(2 x-x^{2}+5\right)$ and $(-4 x-3+7 x)$ from 5 .
$5-\left\{\left(2 x-x^{2}+5\right)+\left(-4 x-3+7 x^{2}\right)\right\}$
$=5-\left(2 x-4 x-x^{2}+7 x^{2}+5-3\right)$
$=5-2 x+4 x+x^{2}-7 x^{2}-5+3$
$=5-5+3-2 x+4 x+x^{2}-7 x^{2}$ (Combining like terms)
$=3+2 x-6 x^{2}$ (Combining like terms)
Thus, the answer is $3+2 x-6 x^{2}$.
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