Given the task definition and input, reply with output. In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.

When Cardano applied it to the formula, "x cubed equals 15x plus 4," it gave an answer involving the square root of  "negative 121," but he knew the equation had "x equals 4" as a solution, so he showed that it could work with quantities more general than real numbers. A false proof it was given by Leibniz when he asserted that "x to the fourth plus t to the fourth" could not be written as a product of two real quadratic factors, but he didn't notice that the square root of "i"could be written in the form "a plus (b times i). "   It simply states that every polynomial equation of degree "n" with complex coefficients has "n" roots in the complex numbers. FTP, name this basic theorem of mathematics.	

Science