When I was a kid, on our old Mac OS7, we had a program simply named 'Graphing Calculator'. Besides graphing functions, it had a feature I've never seen before or since: the ability to interact with an equation and perform algebraic transformations. E.g. if you had 'x = 3y', you could select the '3' and drag it to the other side of the equals sign and the equation would automatically be transformed into 'x/3 = y'. Does anybody know of a
modern, Windows-compatible (or online) app that does that sort of thing? Because I semi-frequently have to do that sort of stuff, and doing it manually is error-prone.