So because it’s a triangle, we can assume that the other angle opposite the 6x+2, must also be 6x+2. Therefore, since angles in a triangle add up to 180, we can do: 6x+2 + 6x+2 + 116 =180.
Now we can collect like terms and get:
12x+4+116=180
Now 180- (4+116) is 60
Therefore, 12x=60
And x = 5 when you divide both sides by 12.
Hope that helps