slope of a line
• m = slope
• (x_1,y_1) = coordinates of the first point in the line
• (x_2, y_2) = coordinates of the second point in the line
slope-intercept form (equation of the line)
• m = slope
• b = y-intercept
point-slope form
• m = slope
• (x_1, y_1) = any point on the line
midpoint (middle point between two points)
• (x_m,y_m) = coordinates of the midpoint
• (x_1,y_1) = coordinates of the first point
• (x_2,y_2) = coordinates of the second point