Answer
$[-16,2]$
Work Step by Step
$-3|x+7|\geq-27\qquad $ ... divide with $(-3)$
... $\times $(negative) $\Rightarrow $ change direction
$|x+7|\leq 9$
... $|u| \leq c $ is equivalent to $-c \leq u \leq c.$
$-9\leq x+7\leq 9 \qquad $ ... add $-7$ ...
$-16\leq x\leq 2$
Borders are included,
The solution set is $[-16,2].$
