Graphing Lines and Line Slope

The first screen shows us how to calculate line slope by coordinates of two points using formula
m = (y₂ - y₁)/(x₂ - x₁).
The second one explains m and b in the equation y = mx + b
The third screen explains the equation y - y₁ = m(x - x₁).
Click on the last icon if you have understand everything to start the game.