So far in this course we have not been given any formula for solving third degrees polynomials.
I was thinking about doing it like this
But that didn't help because the solutions to the roots of that one is in the complex plane which is a foreign word in this book.
It is a third degree so I know it can have at most three roots, there is only one (0) from looking at the graph. But I still don't get how to do this by calculation.
Is there some "trick" I don't see or something I can assume?