Factor the expression completely.

To factor the expression \(100x + 1000\) completely, we can first factor out the greatest common factor (GCF), which is \(100\):

\[
100x + 1000 = 100(x + 10)
\]

Thus, the completely factored form of the expression is:

\[
100(x + 10)
\]

So, the correct response is:

**100(x+10)**