Question 1002277
G is a function of M.
G, gallons remaining in the tank
M, number of miles driven starting from full tank


{{{G=4.5-(1.4/63)*M}}}


The slope can be changed in appearance if it makes viewing or using easier.
{{{1.4/63=14/630=(2*7)/(2*5*7*9)=1/45}}}


This means, {{{highlight(G=4.5-M/45)}}}.


Recognize that the restriction on this application should be that {{{4.5-M/45>=0}}},
{{{4.5>=M/45}}}
{{{4.5*45>=M}}}

{{{M<=202.5}}}.


Also, any miles driven must be non-negative.  Either some miles were driven or they were not; and you cannot drive negative miles of distance.
{{{0<=M<=202&1/2}}}------Important requirement for any full tank of fuel on this vehicle.