Last years utility bill (in dollars) for a sample of homes is estimated by the multiple regression equation = 300 + 7x1 + 13x2,

Last year’s utility bill (in dollars) for a sample of homes is estimated by the multiple regression equation ŷ = 300 + 7x1 + 13x2, where x1 is the number of occupants and x2 is the number of rooms in the home.
a. Identify the y-intercept and partial regression coefficients.
b. If 3 people live in a 6-room home, what is the estimated bill?