First, move like terms on one side. Next, add them and divide. See the attachment for solution.
First lets remove the initial fee

150 is how much she is charging you per hour.
If each hour is 55, lets divide 150 by 55.

She charged you for 2.7 hours (almost 3) of service
57 degrees because vertical angles are the same measure
6 - 2 2/7 =
6 - 16/7 =
42/7 - 16/7 =
26/7 or 3 5/7