Let the larger angle by x^o and smaller angle be y^o.

We know that the sum of two supplementary pair of angles is always 180^o.

According to the question,

x + y = 180^o……………. (1)

x – y = 18^o ……………..(2)

From (1), we get x = 180^o – y …………. (3)

Substituting (3) in (2), we get

180^o – y – y =18^o

162^o = 2y

y = 81^o ………….. (4)

Using the value of y in (3), we get

x = 180^o – 81^o

= 99^o

Hence, the angles are 99^o and 81^o.