If you have an equality of the form...
[tex](x+a)\cdot(x-b)\ge0[/tex]
The inequality can be writen as...
[tex]a\leq x\leq b[/tex]
I'll show you how it looks like on the graph
the graph indicates that x is any value less than or equal to -6 or greater than or equal to 3, which is the red area
[tex]\begin{gathered} x\leq-6 \\ x\ge3 \end{gathered}[/tex]
