解：∵√B=3∴B=9∵AB＜0，B=9＞0∴A＜0∵┃A┃=2∴A=-2∴A-B= -2-9= -11
A=2或-2B=9A*B<0 A=-2A-B=-2-9=-11
B=9A=+-2AB<0A=-2A-B=-11
-11
