Answer:
x = 10
Step-by-step explanation
The exterior angle = the sum of the 2 interior angles (which is the other way to solve the other problem you just posted.)
-10 + 14x = 60 + 7x Add 10 to both sides
-10+10+14x =60+10+7x Combine
14x = 70 + 7x Subtract 7x from both sides
14x-7x = 70+7x-7x Combine
7x = 70 Divide by 7
7x/7 = 70/7
x = 10
