Answer:
x = 17.5 and y = 35
Explanation:
2x + 10 = y + 10 ( alternate angles )
subtract 10 from both sides
2x = y ⇒ 6x = 3y → (1)
the sum of the 3 angles in the triangle = 180°
6x + y + 10 + 30 = 180 ( replace 6x by 3y )
3y + y + 40 = 180
4y + 40 = 180 ( subtract 40 from both sides )
4y = 140 ( divide both sides by 4 )
y = 35
substitute y = 35 into (1)
2x = 35 ( divide both sides by 2 )
x = 17.5