Linear equation

Analytical Geometry Formulas and Equations: Midpoint Formula of P(x1, y1), P?(x2, y2): Distance Formula of P(x1, y1), P?(x2, y2): Slope-Intercept Form y = mx + b Point-Slope Form y2 - y1 = m(x2 - x1) General Form of a Line Ax + By + C = 0 Standard Form of a Line Ax + By = C *Slope of line is (?A/B) Slope of P(x1, y1), P?(x2, y2): *Slopes of parallel lines are equal *Slopes of perpendicular lines are opposite and reciprocal Directed Distance from line Ax+By+C=0 to point P(x1, y1) * The sign of the denominator is the same sign as ?B? in the line. *The directed distance will be positive if the point P is above the line, and negative if P is below the line. Directed Distance Between 2 Parallel Lines *The parallel lines are: Ax+By+C & Ax+By+C?