Paul is a salesperson who earns both a salary and a commission on units sold. in one week, he sold 25 units and earned $1,200. in another week, he sold 20 units and earned $1,075. which of the following slope-intercept form equations models paul’s weekly pay in terms of units sold? . a. y=25x+575. b. y = 25x + 1,200. c. y=-1/25x-68. d. y=1/25x-23