what if the radical is in the denominator?

$\displaystyle y=\frac{2}{x^2+8x+10}$

the domain is $\displaystyle \{x|x^2+8x+10\ge 0\}$

so the domain is $\displaystyle x^2+8x+10\ge0$

$\displaystyle \frac{4ac-b^2}{4a}$

$\displaystyle \frac{40-64}{4}$

$\displaystyle -4$

$\displaystyle x\ge-4$??

range: ??

is this correct?