Answer:
Step-by-step explanation:
By adjacent interior angles theorem,
If a transversal line 'r' intersects two parallel lines 'm' and 'n' then the consecutive interior angles are supplementary.
a° + (3x - 18)° = 180°
a° = 180° - (3x - 18)°
By vertical angles theorem,
If two straight lines intersect each other at a point, opposite angles formed are equal in measure.
180° - (3x - 18)° = (5x - 10)°
(5x - 10) + (3x - 18) = 180
(5x + 3x) - (10 + 18) = 180
8x - 28 = 180
8x = 180 + 28
8x = 208
x = 26
