Answer:
g(x) = 3f(-x/2)
Explanation:
g(x) is 3 times the height of f(x), and 2 times its width. It is also reflected over the y-axis.
The relevant transformations are ...
g(x) = k·f(x) . . . . scales f(x) vertically by a factor of k
g(x) = f(-x) . . . . . reflects f(x) over the y-axis
g(x) = f(x/k) . . . . scales f(x) horizontally by a factor of k
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The three transformations we described at the beginning mean that g(x) is ...
g(x) = 3f(-x/2)