Supplementary angles are angles whose sum is equal to 180°.
Let one angle be x
The other angle is said to be 26°more than the other so it is x + 26
x + (x+26) = 180
x + x + 26 = 180
2x = 180 - 26
2x = 154
x = 154/2
x = 77
1st angle, x, is equal to 77°
2nd angle, x + 26°, is 77° + 26° = 103°
77° + 103° = 180°
180° = 180°