Question

Please help i dont understand

Answer 1

D

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 = (x + 1)/(3) \\\\\ f(x) = (x + 1)/(3) \\\\\ f(x) = (1)/(3)x + (1)/(3)`

I hope I helped you