So g(x) just means the function of the x term as the original value of this is 2x+1 then this is your starting point, when it says -2g(x) all you have to do is do the same to the other side of the equation so just do (2x+1) x -2 this would be -4x-2 as the signs would change due to the negative 2 as a positive and a negative make a negative so the answer is the second one -2g(x) = -4x-2
Hope this helps x