Answer
(-5,4]
Work Step by Step
$-9\lt 3m+6\leq18\longrightarrow$ subtract 6 from each part
$-9-6\lt 3m+6-6\leq18-6\longrightarrow$ subtract
$-15\lt 3m\leq12\longrightarrow$ divide each part by 3
$-15\div3\lt3m\div3\leq12\div3\longrightarrow$ divide
$-5\lt m\leq4$
A parenthesis indicates that -5 is not included in the solution set, while a square bracket indicates that 4 is included in the solution set.
