Answer:
Option: A.
Explanation:
Hey there!
In the given triangle;
60° +16x° + 40° = 180° { Sum of interior angle of a triangle}
100° + 16x= 180°
16x = 180° - 100°

Therefore, X= 5°.
So, Option A (equation) is used for solving the value of"X".
Hope it helps...