The equation y=3.5x-210 represents the profit made by a manufacturer that sells products for $3.50 each, where y is the profit and x is the number of units sold. What is the profit in dollars when 80 units are sold? (Plz help me asap, and explain to me how so know how or why it was the answer)

Data for the height of a model rocket launch in the air over time are shown in the table. darryl predicted that the height of the rocket at 8 seconds would be about 93 meters. did darryl make a good prediction? yes, the data are best modeled by a quadratic function. the value of the function at 8 seconds is about 93 meters. yes, the data are best modeled by a linear function. the first differences are constant, so about 93 meters at 8 seconds is reasonable. no, the data are exponential. a better prediction is 150 meters. no, the data are best modeled by a cubic function. a better prediction is 100 meters.