what’s the answer and how did you find it ?

Answer:
Since all triangle angles add up to 180°, you can set all the angles equal to 180.
(96 + 2x + (x + 12)) = 180
You can now simplify it together
108 + 3x = 180
Now you can isolate x by itself
180 - 108 = 72
72 / 3 = 24
x = 24