Answer:

Step-by-step explanation:
Corresponding Angles are <em>congruent</em>, therefore you set both angle measures equal to each other:
![\displaystyle 135° = [3x + 15]° → 120 = 3x; 40 = x](https://tex.z-dn.net/?f=%5Cdisplaystyle%20135%C2%B0%20%3D%20%5B3x%20%2B%2015%5D%C2%B0%20%E2%86%92%20120%20%3D%203x%3B%2040%20%3D%20x)
I am joyous to assist you at any time.
Try multiplying if it doesn't work divide
Adjacent angles-
2 angles that share a common vertex, a common side and no common interior points.
The answer is ADJACENT ANGLE
In the attachment this is how i did it! ~Best of Luck~