How can I solve a quadratic equation by factorisation?

There are many ways to solve quadratic equations including completing the square, factorisation and using the quadratic equation.

Factorisation involves breaking the quadratic equation into two sets of brackets that when multiplied together, give the quadratic equation. For the general case without a coefficient x²+bx+c=0, the key to this is finding two numbers that add to make b and also multiply together to make c. Then you can put these numbers into the general brackets (x+c)(x+d) where c and d can be positive or negative.

You can then check this answer by using another method of solving, or by substituting the numbers into the original quadratic and both should give an answer of 0.