Finding the Measure of Angle from Vertical Angles

In a plane, two lines, $l$ and $m$, intersect at point $O$, forming four angles. Angle $AOB$ measures $3x + 15$ degrees, and angle $BOC$ measures $2x + 45$ degrees. If angle $AOB$ and angle $BOC$ are vertical angles due to the intersection of the lines, what is the measure of angle $AOB$?