Tickets to a school basketball game cost $4 for students and $7 for adults. at the end of the night, 168 tickets are sold for a total of $861. how many student tickets are sold?

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?