Answer
True.
The given equation can be written in the standard form of a linear equation: $ax+by=c$
Work Step by Step
$2x+3=x$
$2x-x+3=0$
$x+3=0~~$ ($a=1, b=0, c=-3$)
NOTE: This is a linear equation in the strict sense that it plots a line in the Cartesian plane. However, since the y value is 0, it is necessary to check the definition of a line given by your instructor as some instructors would say that this does not qualify as a linear equation.