What is 98.9940 to the nearest foot ? & 42.426 to the nearest foot

Lindsay used two points, (x,y; ) and (+2.82), to find the equation of the line, y = mx + b, that passes through the points. y2-y, first, she used the definition of slope and determined that the value of mis x, - . given this information, which expression must represent the value of b?

You earn a 12% commission for every car you sell. how much is your commission if you sell a $23,000 car?

Me. i can't figure out this question. give an explanation too. .