Question

F(x) = x2. What is g(x)?

Answer 1

Answer:

B

Step-by-step 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