Jessica is selling books during the summer to earn money for college. She earns a commission on each sale but her own expenses. After a month of driving from neighborhood to neighborhood and walking door to door, she figures out that her weekly earnings are approximately a linear function of the number she knocks on.
She writes the equation of the function likes this: E(x)=7x-25, where x is the number of door she knocks on during the week and E(x) is her earning for the week in dollars. Which w=of the following are reasonable interpretations of the y intercept of Jessica's function?