Answer:
g(x) = f(1/2x)
Explanation:
Look at the graphs, pick a y value and see how x changes from f(x) to g(x) for the same y value.
For example, see the points at y= 2.
You can see that when f(x)=2, x = 2
And when g(x)=2, x = 1
1 is half of 2 so the x in f(x) is multiplied by half to get x for g(x).
You can verify by picking another point such as y=6.
For function f, x= 6.
For function g, x= 3.
Again 3 is half of 6 so g(x) = f(1/2 x).