Coordinate geometry in the (x, y) plane notes

This document contains notes for coordinate geometry in the (x, y) plane. They should be helpful while working with coordinate geometry in the (x, y) plane.

• In the general form;
  
  …where m is the gradient and (0, c) is the intercept on the y-axis.
  In the general form;
  
  …where a, b, and c are integers/
  
• You can work out the gradient m of the line joining the points with coordinates (x, y) to the point with coordinates (x₂, y₂) by using the formula;
  
• You can find the equation of a line with gradient m that passes through the point with coordinates (x₁, y₁) by using the formula.
  
• You can find the equation of the line that passes through the points with coordinates (x₁, y₁) and (x₂, y₂) by using the formula;
  
• If a line has a gradient m, a line perpendicular to it has a gradient of;
  
• If two lines are perpendicular, the product of their gradient is -1