Which of the following is the Inverse of y = 3x?
a) f^-1(x) = 1/3x b) f^-1(x) = 3x c) f^-1(x) = 3/x d) f^-1(x) = x/3

Solution: 

We will be using the concept of inverse function to solve this.

Given that, y = 3x

Let f(x) = y = 3x

Switch x and y

x = 3y

Express y in terms of x.

y = 1/3 x

From the definition of inverse function. f(x) = y ⇒ x = f^-1(y)

⇒ f^-1(y) = 1/3x

Thus, the inverse of y = 3x is f^-1(x) = 1/3x.

Which of the following is the Inverse of y = 3x?

Summary:

The inverse of y = 3x is f^-1(x) = 1/3x.