Anyone know the answer to this question?

The table shows values for functions f(x) and g(x) . x f(x)=3x g(x)=2x+1 −2 19 −3 −1 13 −1 0 1 1 1 3 3 2 9 5 what is the solution to f(x)=g(x) ? select each correct answer.

Cos^2x+cos^2(120°+x)+cos^2(120°-x)i need this asap. pls me

With this question, the answer with the red arrow is incorrect!