Find the solutions of the equation: sin(x - 15degrees) = 0.5 between 0<= x <= 180

Consider a sin graph and all the points on the graph which are equal to 0.5. You'll find that, between one period of a positive sin graph, invsin(0.5) may equal 30 degrees or 150 degrees.
The equation can now be seen as:x - 15 = 30, and x - 15 = 150.
These equations can be solved for x, leading to: x = 45, x=165