Answer:
x = 3
Step-by-step explanation:
The exterior angle of a triangle is equal to the sum of the 2 opposite interior angles.
28x - 2 is an exterior angle of the triangle, thus
28x - 2 = 15x - 3 + 40 = 15x + 37 ( subtract 15x from both sides )
13x - 2 = 37 ( add 2 to both sides )
13x = 39 ( divide both sides by 13 )
x = 3
