Jae is a real estate photographer. The amount he earns in one week is a linear function of the number of houses he photographs. If he photographs 3 houses, he earns $390, and if he photographs 5 houses, he earns $620.
a. Create a linear model for Jae's earnings (y) (in dollars) as a function of the number of houses he photographs (x) and put the model in slope-intercept form.