Answer:
x = 40
Step-by-step explanation:
All angles in a triangle add up to 180
(3x-10) + 30 + x = 180
4x = 160
Answer: x = 40
All the interior angles of a triangle add up to 180°
Therefore,
30 + 3x - 10 + x = 180
30 + 4x - 10 = 180
20 + 4x = 180
