Answer
$-2387$
Work Step by Step
Here, $a_1=7, r=-2, n=10$
Now, we have
$S_n=\dfrac{a_1(1-r^n)}{1-r}$
Now,
$S_{10}=\dfrac{7(1-(-2)^{10})}{1-(-2)}$
or, $=-2387$
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