Answer :
To solve this problem, we will solve each inequality for x and the solution to the system will be the intersection of the solution sets.
1) Solving the first inequality for x we get:
[tex]\begin{gathered} 3x+12\ge-9, \\ 3x\ge-9-12, \\ 3x\ge-21, \\ x\ge-\frac{21}{3}, \\ x\ge-7. \end{gathered}[/tex]2) Solving the second inequality for x we get:
[tex]\begin{gathered} 9x-3\le33, \\ 9x\le33+3, \\ 9x\le36, \\ x\le\frac{36}{9}, \\ x\le4. \end{gathered}[/tex]Answer:
[tex]x\ge-7\text{ and x }\le4.[/tex]