Word Problem Emergency?

Question

Write a linear equation and solve. Please Help!

A car used 14 gallons of gasoline and traveled a total distance of 550 miles. The car's fuel efficiency is 40 miles/gallon on the highway and 35 miles/gallon in the city. How many gallons of gasoline were used on the highway?

Answer 1

x+y=14

40x+35y=550

y=14-x

40x+35(14-x)=550

40x+490-35x=550

5x=60

x=12

Answer 2

12 gallons were used on the highway. I can't think of a linear equation :/ sorry.