Answer:
x = 25.4
Explanation:
the exterior angle of a triangle is equal to the sum of the 2 opposite interior angles.
139° is an exterior angle of the triangle, then
5x - 25 + 37 = 139
5x + 12 = 139 ( subtract 12 from both sides )
5x = 127 ( divide both sides by 5 )
x = 25.4