Ch P is mainly about linear equations. Linear equations come in different forms. There's pt- slope form, (y-y1)=m(x-x1), where you use the slope and one pt in the graph to find the equation. Another, and the most commonly used is the slope-intercept form, y=mx+b. Y equals the vertical position of a pt.(y-axis), x equals the horizontal position of a pt.(x-axis), and b is the y-intercept.