Quadratic equations are polynomials, meaning strings of math terms. An expression like “x + 4” is a polynomial. They can have one or many variables in any combination, and the magnitude of them is ...

Quadratic equations can have two solutions, or roots, and we already know one of them: Since (0, 5) is a point of intersection of the line and the circle, x = 0 must be a solution to our equation.