Why is the graph wrong
and how would a fixed one look like

It's wrong because they are being paying $3 each day so it would be $3, $6, $9, $12, $15, $18 and so on. Not $5, $8, $11, and $14.

slope is 35 and 20 miles is the y-intercept.

step-by-step explanation:

hello from mrbilldoesmath!

answer:   x^2 + y^2 = 1024

discussion:

the equation of a circle with center (h,k) and radius "r" is

(x-h)^2 + (y-k)^2 = r^2.

in our case

(x-0)^2 + (y-0) ^2 = 32^2 = 1024

you,

mrb