# How do you find the domain and range of x+3 =0?

Apr 17, 2017

$\textcolor{red}{x + 3 = 0}$ is an equation
It is not a function.
The terms "domain" and "range" only apply to functions.

#### Explanation:

Possibility 1: You really wanted the solution
$\textcolor{w h i t e}{\text{XXX}} x = - 3$

Possibility 2: You wanted the domain and range of $f \left(x\right) = x + 3$
$\textcolor{w h i t e}{\text{XXX}}$Domain: x in RR (or CC)color(white)("xxxx)all possible values of $x$ are valid
$\textcolor{w h i t e}{\text{XXX}}$Range: $f \left(x\right) \in \mathbb{R} \left(\mathmr{and} \mathbb{C}\right) \textcolor{w h i t e}{\text{xxx}}$any value can be generated using a suitable value for $x$

Possibility 3: This was a trick question if see if you knew that the terms do not apply to equations

Apr 17, 2017

domain: $\left(- 3\right)$
range: $\left(- \infty , \infty\right)$

#### Explanation: domain: the range of values $x$ could take

$x + 3 = 0$
$x = 0 - 3 = - 3$

here, $x$ can only take one value, so the domain is $\left(- 3\right)$

range: the range of values $y$ could take:

since the only condition for the line is that $x = 0$, $y$ could take any real value,
so the range is $\left(- \infty , \infty\right)$