Question

Which of the following expressions is the inverse of the function y=3x+4

Answer 1

To find the inverse of a function, we swap x and y then solve for y
So with this, we take y = 3x + 4 and make it x = 3y + 4. Now we solve for y
x = 3y + 4
Subtract 4 from both sides
x - 4 = 3y
Divide both sides by 3
$\frac{x-4}{3} =y$

Answer 2

Options:

A. y = 3x - 4

B. y = -3x - 4

C. y = x - 4 / 3

D. y = x + 4 / 3

The answer is option C when your doing inverse functions you need to switch the variables but substituting x with y. So, the equation would look like this:

• y = 3x + 4 ---> x = 3y + 4
• x = 3y + 4
• Subtract 4 on both sides:
• Then divide 3 on both sides: " $\frac{x - 4}{3} =y$ or option C "

Hope this helps!