Form the pair of linear equations for the following problems and find their solution by substitution method. The larger of two supplementary angles exceeds the smaller by 18 degrees. Find them.

Let the smaller angle be x.
The larger angle is x + 18.
Since the angles are supplementary, their sum is 180 degrees.
Therefore, we can write the equation:
x + (x + 18) = 180
2x + 18 = 180
2x = 180 - 18
2x = 162
x = 162 / 2
x = 81
The smaller angle is 81 degrees.
The larger angle is x + 18 = 81 + 18 = 99 degrees.
Therefore, the two supplementary angles are 81 degrees and 99 degrees.