In this applet you can graph a two-variable linear equation in standard form ([math]Ax+By=C[/math]) on the left and a two-variable linear equation in slope-intercept form ([math]y=mx+b[/math]) on the right. This is useful if you're given an equation in standard form and asked to graph it using slope-intercept form -- you can make sure you get the same graph on both sides, which means your slope-intercept form is correct.
