This is definitely different. Maybe if the equation is in the form of how it is written and not in one line (lol the asterisks), it would have been better. Maybe add more tick marks in between and also a grid. Like what others have said, more functions, negative, exponents, log, parenthesis and a more detailed look. This game really has potential.

Idea needs polishing to make it more fun.

An okay game. Good concept, but it's too restricting. Try adding other equation types and making the graph a bit easier to read, as sometimes I couldn't tell exactly where the dot was, as in it's coordinates.

I don't like maths, nice game tough.

I agree with Koda in that you could extend the possibilities of (more complex) equations.
It's a great concept! Finally something I haven't seen before.