You can move the points using the slider. Two lines only meet at one point. When they meet the solution for each equation is the same i.e. the values for x and y are the both the same. For any other value of x the values for y are different for each equation.

You can change the equations by typing new equations into the Input box - but you must type it as in the examples below. [br]To input x - y = 5 and 2x + y = 6 you type[br]a:x - y = 5 and press enter on the keyboard and [br]b:2x + y = 6 and press enter on the keyboard