Answer
The solution set is $\left\{x | x \geq \frac{4}{3}\right\}$
Work Step by Step
Add $-4 x$ to both sides:
\[
\begin{array}{c}
9-2 x-4 x \leq 4 x+1-4 x \\
9-6 x \leq 1
\end{array}
\]
Add $-9$ to both sides:
\[
\begin{aligned}
9-6 x-9 & \leq 1-9 \\
-6 x & \leq-8
\end{aligned}
\]Divide both sides by $-6$.
Since the number divided to both sides is negative, $\leq$ changes to $\geq$:
\[
\begin{array}{c}
\frac{-6x}{-6}\geq\frac{-8}{-6} \\
x \geq\frac{4}{3}
\end{array}
\]
Therefore the solution set is $\left\{x | x \geq \frac{4}{3}\right\}$.
