How do you factorize a quadratic expression?

Firstly, your quadratic equation will be of the form ax² + bx + c where a, b and c will be numbers. Now you have to multiply a by c to get a number, say d. From this number d, you need to find 2 factors of it that add to make b. You split your middle term accordingly and then your expression can be split into 2 parts, which are factorized seperately.