Answer
$0$
Work Step by Step
Substituting $
x
$ with $
3
$, then the given expression, $
[x+3(2-5x)\div7+x](x-3)
$, evaluates to
\begin{array}{l}\require{cancel}
[x+3(2-5(3))\div7+3](3-3)
\\\\=
[x+3(2-5(3))\div7+3](0)
\\\\=
0
.\end{array}