Write an equation in slope intercept form that passes through (2,1) and is perpendicular to (5x+y=9)

Asmall foreign car gete 42 miles per gallon and user 35 gallons on a trip. gasoline costs $1.05 per gallon. what was the cost of gasoline per mile driver?

Sanya noticed that the temperature was falling at a steady rate of 1.4 degrees every hour from the time that she first checked her outdoor thermometer. by 6 a. m., the temperature had fallen 21 degrees. which expression can you use to find how many hours earlier she had first checked the thermometer?

Can someone answer this question for me