Yes, you are correct.
Hope my answer helped u :)
The slope of the line is 2 if that is what you're looking for
He uses 15 gallons. Because 270/6 = 45. Meaning he drives 45 miles per gallon. So 675/45=15. 15 gallons he will need to use to drive 675 miles.
Ts temperature as a function of time is given by T(t)=a(1-e^kt)+b
the values of a and b area = 50 Fb = 350 F
this is very evident to equation the b is the initial temperatre of the oven which is 350 F
and also a is the initial temperature of the potato because it is the term multiplied by the exponent term which will indicate the temperature increasse of the potato