A scaled version means that our leading coefficient will change. Let's set up an equation to find our leading coefficient, a.
g(x) = a * x^2
Now that we have our equation, we need a point that is on g(x). The point given is (4,8). Let's use that point and plug x and y into our equation so that we can solve for a.
8 = a * (4)^2
8 = a * 16
a = 1/2
All that's left to do is plug in our a value into g(x).
g(x) = 1/2 x^2
Hope this helps!! :)