Chapter P talks about the linear equation. A linear equation can be represented by the general form Ax+By+C=0 which you can use to find the x-intercept and y-intercept. The equation can be transform into different forms, such as point-slope form or slope-intercept form, depending on what information is given and what you're trying to find. Point-slope form gives you a point and the slope and can be use to find a linear equation. While, the slope-intercept form gives you the slope and y-intercept and can be use to graph a line in a graphing calculator.