How do you find the domain of f (x) = -1 / ( x + 3)?

Mar 19, 2018

The domain of a function is a set of all x, for which the function exists or $f$ be defined
In our case, the only value for $f \left(x\right)$ does'nt exist is $- 3$
En efect: if $x = - 3$ then $f \left(- 3\right) = - \frac{1}{- 3 + 3} = - \frac{1}{0}$. There is no number which multiplied by 0 gives -1
For this reason the domain is $\mathrm{do} m \left(f \left(x\right)\right) = \left\{x \in \mathbb{R} / x \ne - 3\right\}$