Answer:
A transformation of (0,4), in order words, adding 4 to all your y-values.
Explanation:
If you were to plot f(x) and g(x), you'd notice that all the y-values have been moved up by 4. To prove this to yourself, lets take the y-intercept.
Let x = 0, then g(0) = 2 and f(0) = -2, as you can see the y-value of the intersect has been shifted upwards by 4. Therefore, it can be said that f(x) has been shifted by (0,4), so f(x) +4 = g(x).