Answer:
x=7
Explanation:
Step #1- Set the two lines equal to each other
10+12=x+15
Step #2- Solve for the line you have all values for
10+12=22
Step#3- Plug 22 back into the equation where the two lines are set equal to each other
22=x+15
Step #4- Solve for X algebraically
22=x+15
22-15=x
7=x