First, let us suppose that a = b. then we'll multiply both sides by a, which gives us a² = ab. add (a²  2ab) to both sides a² + (a²  2ab) = ab + (a²  2ab). of course this can be simplified to 2(a²  ab) = a²  ab. And finally, now that you're keen, divide both sides by a²  ab, whereby we get:

