How was x and y found for promblem 26

(8y + 2) + (25y - 20) = 180  {interior angles on the parallel lines add up to 180)

Remove brackets:
8y + 2 + 25y - 20 = 180

Combine like terms:
33y - 18 = 180

Add 18 to both sides:
33y = 198

Divide both sides by 33:
y = 6

y = 6

(10x) + (8y + 2) = 180 {Adjacent angles on a straight line add up to 180)

Plug y = 6 into the equation:
(10x) + (8(6) + 2) = 180 

Evaluate the bracket:
10x + 50 = 180

Subtract 50 from both sides:
10x = 130

Divide both sides by 10:
x = 13

x = 13