Observe the figure clearly.
Statement 1:

Reason 1: Given
Statement 2:

Reason 2: Angle addition postulate
Statement 3:

Reason 3: Substituting the values of the measures of the given angles.
Statement 4:

Reason 4: Addition of the like terms
Statement 5:

Reason 5: Subtraction property of equality
Statement 6:

Reason 6: Division property of equality