Answer:
x = 20 , y = 100
Explanation:
the exterior angle of a triangle is equal to the sum of the two opposite interior angles
(7x - 40)° is an exterior angle of Δ ABC
3x° and 2x° are the two opposite interior angles to it , then
7x - 40 = 3x + 2x
7x - 40 = 5x ( subtract 5x from both sides )
7x - 5x - 40 = 5x - 5x ( simplify both sides )
2x - 40 = 0 ( add 40 to both sides )
2x - 40 + 40 = 0 + 40 , that is
2x = 40 ( divide both sides by 2 )
x = 20
then
7x - 40 = 7(20) - 40 = 140 - 40 = 100
7x - 40 and y are vertically opposite angles and are congruent , so
y = 7x - 40 = 100