# Math Help - Factorisation quadratic

1. ## Factorisation quadratic

Hi I cant seem to factorize x^2-2x-1
I need to arrange it so it can be multiplied out ( )( )
Help please?

2. Originally Posted by wolfhound
Hi I cant seem to factorize x^2-2x-1
I need to arrange it so it can be multiplied out ( )( )
Help please?
Use the quadratic formula: $x = \dfrac{-b\pm\sqrt{b^2-4ac}}{2a}$. Find two values of x, and then write them in the form ( $x-\alpha)(x-\beta)$, where $\alpha$ and $\beta$ are the two solutions of the equation.

3. Originally Posted by wolfhound
Hi I cant seem to factorize x^2-2x-1
I need to arrange it so it can be multiplied out ( )( )
Help please?
That's because it doesn't factorise neatly. Find $b^2-4ac$ and then if it's a perfect square it will factorise, if not it won't