Lines, Angles, & Triangles Practice Test

In triangle $ABC$, the measures of angles $A$ and $B$ are $42^\circ$ and $71^\circ$, respectively. What is the measure of angle $C$?

At a point, two lines intersect forming vertical angles. One of the angles is labeled $(5x-15)^\circ$, and its vertical angle is labeled $(3x+25)^\circ$. What is the value of $x$?​​