# How do you factor #y= x^2 - 10x - 9# ?

##### 1 Answer

Prime; or,

#### Explanation:

We need to look for numbers whose SUM is

The pairs we could use to have a product of

This means the expression is **PRIME**, if we limit ourselves to integers.

However, if we throw irrationals into the mix, we can use the quadratic formula or complete the square to find this quadratic's irrational roots.

Thus, the roots of this are

Normally, if a root were, say,

You could rewrite

We can do the same for the irrational monstrosity we have:

#x-5-sqrt34=0#

#x-5+sqrt34=0#

Thus, factored, we get