Find the domain and the range of each of the following real
function: $f(x)=\frac{3 x-2}{x+2}$
Given: $f(x)=\frac{3 x-2}{x+2}$
Need to find: Where the functions are defined.
Let, $f(x)=\frac{3 x-2}{x+2}=y$ .......(1)
To find the domain of the function f(x) we need to equate the denominator of the function to 0.
Therefore
$x+2=0$
$\Rightarrow x=-2$
It means that the denominator is zero when $x=-2$
So, the domain of the function is the set of all the real numbers except $-2$.
The domain of the function, $\operatorname{Df}(x)=(-\infty,-2) \cup(-2, \infty)$.
Now, to find the range of the function we need to interchange $x$ and $y$ in the equation no. (1)
So the equation becomes,
$\frac{3 y-2}{2+y}=x$
$\Rightarrow 3 y-2=2 x+x y$
$\Rightarrow 3 y-x y=2 x+2$
$\Rightarrow y=\frac{2 x+2}{3-x}=f\left(x_{1}\right)$
To find the range of the function $f\left(x_{1}\right)$ we need to equate the denominator of the function to 0 .
Therefore
$3-x=0$
$\Rightarrow x=3$
It means that the denominator is zero when $x=3$
So, the range of the function is the set of all the real numbers except 3 .
The range of the function, $\mathrm{Rf}(\mathrm{x})=(-\infty, 3) \cup(3, \infty)$.