[math]x+y=6 [/math] [math]xy=6[/math] Solve the first equation for [math]y[/math]: [math]y=6-x[/math] Plug that into the second equation: [math]x(6-x)=6[/math] Simplify into the regular form of a quadratic equation: [math]6x-x^2=6[/math] [math]x^2–6x+6=0[/math] From this point, just use the quadratic equation to arrive at: [math]x=3\pm\sqrt{3}[/math] Which means that [math]y=3\mp\sqrt{3}[/math] … Whenever you get a problem like this, your first step should be to render into down into a set of algebraic equations. At that point, it becomes a simple algebra question. Answer from Henry Smith on quora.com