Answer:
B
Explanation:
Looking at the graph, we can see that g(x) is a compressed version of f(x) in the x direction but stretched in the y direction. We know that it is compressed because the values of g(x) are inside of f(x) in the x direction, and that it is streched because the values of g(x) are higher than the values of f(x) in the y direction.
Next, we want to figure out how much g(x) is a compression/stretch of x.
In the y direction, at x=1, y=1. At x=3, y=9. The ratio between the y values is 9/1 = 9, so in the y direction, the graph is streched by 9.
A stretch in the y direction can be represented by kf(x), with k representing how much the graph is stretched. In our example, k=9, so we have
kf(x) = 9f(x) = 9(x²) = 9x². This is equal to (3x)² = 9x², or B
In the x direction, at x=1, y=1. At x=3, y=9. The ratio between the x values is 3/1 = 3, so in the x direction, the graph is compressed by 3.
f(kx) represents a compression by a factor of k in the x direction, and k =3 here, so we have
f(kx) = f(3x) = (3x)² = 9x² = B