Answer
$x=59^{\circ}$
Work Step by Step
Since the angles 4 and 5 are supplementary angles, we know they add up to $180^{\circ}$. Thus:
$$\angle 4 + \angle 5 =180^{\circ}\Longrightarrow 2x-3+x+6=180$$
Thus
$3x+3=180$
$3x=177$
Now solve for $x$:
$x=59^{\circ}$
