In this short post I wish to explain how to solve simple quadratic equations with Trinomial factorisation
To solve a quadratic equation in this form there are two main methods you can use to solve these either trinomial (also known as quadratic) factorisation or the quadratic formula. In this article I will explain the factorisation method.
In maths it is always easier to use an example than to explain with words alone.
Ex1: Solve by factorisation x2 + 8x + 12 = 0
1. Break into two brackets with an x in each:
> (x ) (x )
2. Find two numbers that add to give 8 and multiply to give 12. Then place in the other side of each bracket.
> (x 6) (x 2)
3. Put in the sign (+ of -) since the numbers are +ve use a plus sign.
> (x + 6) (x + 2)
4. Multiply out to check:
> (x + 6) (x + 2)
= x2 x 8x + 12
5. Re write as:
> (x + 6) =0
Or
> (x + 2) = 0
This gets more complicated when you use either –ve numbers or start with more than one x2. Here is a worked example:
Ex2: Solve by factorisation 3x2 + x – 4
>(3x ) (x )
> (2x 4) (x 1)
> (2x + 4) (x - 1)
