Question

please help i dont understand

Answer 1

Answer:

D

Step-by-step explanation:

$f(x) = 3x + 1$

Changing x to y and y to x:

$f(x) = 3x + 1 \\\ y = 3x + 1 \\\ x = 3y - 1 \\\ 3y = x + 1 \\\ y = \frac{x + 1}{3} \\\\\ f(x) = \frac{x + 1}{3} \\\\\ f(x) = \frac{1}{3}x + \frac{1}{3}$

I hope I helped you