Answer:
x = 11
Explanation:
interior angles of a triangle = 180
equation:
⇒ 82 + 31 + 6x + 1 = 180
combine like terms:
⇒ 82 + 31 + 6x + 1 = 180
⇒ 114 + 6x = 180
subtract 114 on both sides:
⇒ 114 - 114 + 6x = 180 - 114
⇒ 6x = 66
divide 6 on both sides:
⇒ 6x = 66
⇒

⇒ x = 11