Part 9
solve the first inequality
[tex]9-12r\ge-99[/tex]solve for r
[tex]\begin{gathered} -12r\ge-99-9 \\ -12r\ge-108 \\ mu\text{ltiply by -1 both sides} \\ 12r\leq\text{ 108} \\ r\leq9 \end{gathered}[/tex]the first solution is the interval (-infinite, 9}
Solve the second inequality
we have
[tex]\begin{gathered} -2r-4\text{ }<-12 \\ -2r<-12+4 \\ -2r<-8 \\ m\mu\text{ltiply by -1 both sides} \\ 2r>8 \\ r>4 \end{gathered}[/tex]the solution is the interval (4, infinite)
therefore
the solution of the compound inequality is
(-infinite, 9} ∩ (4, infinite)=(4,9}
All real numbers greater than 4 and less than or equal to 9