Question 59944
The total charge for 210 miles of use was $89.
Let the fixed charge per mile driven be $p
Then the equation is $25 + 210p = 89
==> 210p = 89 - 25 [subtracting 25 from both the sides]
==> 210p = 64
==> 210p/210 = 64/210
==> p = 0.31

so the fixed charge per mile driven = $0.31

The required equation for x miles driven would be 
C = 25 + 0.31x