I have one good book on polynomials. It is called (Level of Knowledge of Polynomials) by its author S. L. Tabachnikov. In principle, I could study it, but I am still mastering the Agebra I. Not long ago reached Themes: sequences. And trying to combine two huge topics of study. As a result, the learning rate decreases of studying general material. I would like to know where there is a possible online platform where polynomials(from basic to advanced placement) could be easily explored.