Quadratic functions and equations are described. A quadratic function is defined as f(x) = ax^2 + bx + c, where a ≠ 0. The graph of a quadratic function is a parabola. A quadratic equation is an equation of degree 2 in the form ax^2 + bx + c = 0, where a ≠ 0. There are three methods for solving quadratic equations: factorizing, completing the square, and the formula method. Factorizing involves factoring the left side of the equation into two binomial factors. Completing the square involves rewriting the equation into the form (x + p)^2 = q and then taking the square root of both sides.