Answer
True
Work Step by Step
A function is a correspondence between a first set, called the domain, and a second set, called the range, such that each member of the domain corresponds to exactly one member of the range.
If we define a function
$f(x)=x$, then
each x in the domain corresponds to itself, so x is in the range as well.
So, Domain $\subseteq$ Range
If y is in the range, then y must also be in the domain, as f(y)=y.
So, Range $\subseteq$ Domain.
Set equality leads to: Domain = Range.
The statement is true.
