Geometry/Algebra Missing Angles

How would you find the missing angle with this setup: a 180 degree line with a right angle coming out, then another right angle forming two angles, one angle is x and the other is x-16.  I need to use an algebraic expression to find x.

x + x - 16 = 90 {the two angles add up to 90 degrees}
2x - 16 = 90 {combined like terms}
2x = 106 {added 16 to both sides}
x = 53 {divided both sides by 2}
x - 16 = 37
missing angles are 53 and 37

- Algebra House