Question

The graph of function g is a vertical stretch of the graph of function f ​​by a factor of 3. Which equation describes function g?

​​g(x)=f(x/3) ​
g(x)=3f(x)
​​g(x)=f(3x) ​, ​
g(x)=1/3f(x)

Answer 1

• B) g(x) = 3f(x)

Explanation:

What is a vertical stretch?

Given a function f(x), a new function g(x) = cf(x), where c is a constant, is a vertical stretch of f(x) when c > 1.

In our case the function f(x) is stretched by a factor of 3.

It means c = 3 and therefore:

• g(x) = 3f(x)

Correct choice is B