You can
put this solution on YOUR website!i am not sure waht you mean...you have written something that is ambiguous.
You could mean

in which case we have:

or

. Now divide by -1
and hence
or you meant

in which case we have:

. Now divide by -1
and hence
Both situations use the same rules, namely if you multiply or divide by a negative number, the inequality sign swaps round.
jon