Answer:
x = 10, x = 5
Step-by-step explanation:
The exterior angle of a triangle is equal to the sum of the 2 opposite interior angles.
(13)
12x + 8 is an exterior angle of the triangle , then
12x + 8 = 7x - 9 + 67
12x + 8 = 7x + 58 ( subtract 7x from both sides )
5x + 8 = 58 ( subtract 8 from both sides )
5x = 50 ( divide both sides by 5 )
x = 10
(14)
13x - 5 is an exterior angle of the triangle , then
13x - 5 = 5 + 3x + 40
13x - 5 = 3x + 45 ( subtract 3x from both sides )
10x - 5 = 45 ( add 5 to both sides )
10x = 50 ( divide both sides by 10 )
x = 5
