PLEASE HELP NEED DONE ASAP

Answer:
x = 12
Step-by-step explanation:
By the alternite intereor angle therom, the two expresions equel each other
8x - 15 = 3x + 45
8x -3x - 15 = 3x - 3x + 45
5x - 15 = 45
5x - 15 + 15 = 45 + 15
5x = 60
5x/5 = 60/5
x = 12