Can someone help me with this I’m in the middle of a test and really don’t know what I’m doing

Answer:
x = 9
Step-by-step explanation:
they are equal to each other
3x + 15 = 5x - 3
subtract 3x from borh sides
15 = 2x -3
add 3 to both sides
18 = 2x
divid both sides by 2
9 = x
Answer:
x=9
Step-by-step explanation:
Since they are corresponding angles, they are the same value. We can then put these two equations equal to each other and solve for x.