Question

Please help me answer this!!!

Answer 1

$a_1$ is the first term of the sequence, which is $\boxed{-4}.$

$r$ is the common ratio of the sequence, the number that you multiply one term by to generate the next term. Here, we see that multiplying by -2 will generate the next term, so $\boxed{r=-2}.$

We use the formula $S_n=\frac{a_1(r^n-1)}{r-1}$ to find the sum of the first 6 terms - just plug in our values for $a_1$ and $r:$

$S_6=\frac{-4((-2)^6-1)}{-3}=\frac{-4(63)}{-3}=\boxed{84}.$