# Find the domain of the function.

#### mitchconnor

##### New member
Find the domain of the real valued function:

f(x)=x−10−−−−−√x2+9x+8=x−10−−−−−√(x+8)(x+1)

Why does the x2+9x+8 become (x+8)(x+1)?

Thanks for the help!

#### Ackbach

##### Indicium Physicus
Staff member
Find the domain of the real valued function:

f(x)=x−10−−−−−√x2+9x+8=x−10−−−−−√(x+8)(x+1)

Why does the x2+9x+8 become (x+8)(x+1)?

Thanks for the help!
I'm not entirely sure what mathematical operation is occurring between the $x-10$ and the $\sqrt{x^{2}+9x+8}$. Could you please clarify that for me?

As for $x^{2}+9x+8=(x+8)(x+1)$, that is a straight-forward factoring problem. If you multiply the RHS out, you will get the LHS.