nothing else is given, so for the two triangles to be congruent, the only possible proof is the ASA theorem.
first pairs of angles: 2x+7=x+21 => x=14
second pairs of angles: 8y-4=4y+28 =>y=8
The two triangles share the same side PR
Based on the Angle-Side-Angle Triangle Congruence theorem, these two triangles are congruent with x=14, y=8
(2x+7) +(8y-4) +Q=180 =>85