The solutions to the questions are as follows:
- \(x = -2\)
- The dishwasher will use \(80\) gallons for \(10\) loads.
- The net translation is \(-3\) units down.
Thus, the final answers are:
\[
\boxed{x = -2}
\]
\[
\boxed{80 \text{ gallons}}
\]
\[
\boxed{-3 \text{ units down}}
\]