#### Answer

$\color{blue}{[-5 , +\infty)}$

#### Work Step by Step

Add $8$ to both sides:
$-3x-8+8 \le 7+8
\\-3x \le 15$
Divide $-3$ to both sides.
Since a negative number was divided to both sides of the inequality, the inequality symbol will be reversed.
$\dfrac{-3x}{-3} \ge \dfrac{15}{-3}
\\x \ge -5$
In interval notation, the solution set is:
$\color{blue}{[-5 , +\infty)}$