Quadratic equations

What are quadratic equations?


Quadratic equations are equations which can be written as:

How do I solve a quadratic equation?


There are two ways of solving quadratic equations. The first way is to think of two numbers which add up to equal b & which multiply to give c.

Lets try an example, lets solve the equation ...



Now, what two numbers add together to give 3 and multiply together to give 2?

Well, the numbers 1 & 2 add together to give 3 & multiply together to give 2. Don't worry if you find this complicated. Just like everything with math, the more you practice it, the easier it will become to work out the two numbers.

Now we've worked out the two numbers which add together to make b (3 in this example) and multiply together to give c (2 in this example) you can just rewrite the equation using these two numbers.




Let's try another example. Let's solve the equation ...



So, what two numbers add to give 1 and multiply to give -12.

Well, we know that ...

So, the two numbers we need here are -3 & 4!

So, the equation ...



Using a formula to solve a quadratic equation


The other way of solving quadratic equations is to us a formula.

Remember, a quadratic equation is any equation which can be written as ...

where the letters a, b & c represent fixed numbers, such as 3, 7, 1001 or anything else.


So, to solve a quadratic equation, you can simply replace the letters in these formulae with the numbers from your equations.

So, to solve the equation ...


Try and practice solving quadratic equations for yourself - click here!