Since it is a given that the angles are vertical, then that means they have to be congruent or = to each other so we can now set up an equation:
3x+7=x+53
Now we need to get the variable alone on one side so subtract 7 from the left (remember what you do, you must do to both sides)
3x=46
Now we can divide by three to get x alone
x=15.333333333 or rounded to 15.33
