The equation we would use here would be 45 + 0.75x = C
This is because we have a flat fee of $45 and you are being charged $0.75 per mile, so it depends on how many miles were driven.
To find out how much it would cost if it were to drive 110 miles, we simply put 110 in place of x;
45 + 0.75(110) = C
And now we solve!
45 + 82.50 = C
$127.50
Hope this helps!