Help me, not sure how to solve this, my teacher didn't teach us yet, and I want a solid understanding of it, so the answer will be great! Also will give the most brainliest!

Step-by-step explanation:
10 + 5x = 10 + 5(15)
= 10 + 75
= 85°
4x - 10 = 4(15) - 10
= 60 - 10
= 50°
6x - 5 = 6(15) - 5
= 90 - 5
= 85°