Anyone who has studied mathematics to some degree will know about algebraic equations. An algebraic equation is an equation that can be solved to find the unknown value of **x**. A quadratic equation is an algebraic equation with **x²**, or in other words has two valid solutions to x. Generally speaking, a quadratic equation can be expressed in the following fashion: **ax² + bx + c = 0**. a, b and c are constants and the equation can be solved to find x. A quadratic equation is definitely more complicated to solve compared to a linear equation and it can be solved using various means and applications such as *factorisation*. As these methods are learnt in school and this *Encyclopaedia *is technically not a mathematics textbook, such methods will not be delved into.

If you have not learnt it already, there is a shortcut method to solving quadratic equations: the **quadratic formula**. This formula can easily find x if you simply substitute in the values for a, b and c. Of course this formula only works if the solutions are real numbers. The quadratic formula is as follows:

As you can see, because of the ± sign, the formula can be used to find both solutions to a quadratic equation. Even without factorising, it can find the answer as long as you substitute numbers into it on a calculator, making maths class very easy. However, as mentioned above the *Encyclopaedia of Absolute and Relative Knowledge* is not a mathematics textbook and one should instead learn properly from their teacher, not using the formula until they have been taught it properly.