①當(dāng)a>0,b>0時(shí),x=
a |
|a| |
|b| |
b |
|ab| |
ab |
②當(dāng)a>0,b<0時(shí),x=
a |
|a| |
|b| |
b |
|ab| |
ab |
a |
a |
b |
b |
ab |
ab |
③當(dāng)a<0,b>0時(shí) x=
a |
|a| |
|b| |
b |
|ab| |
ab |
a |
a |
b |
b |
ab |
ab |
④當(dāng)a<0,b<0時(shí),x=
a |
|a| |
|b| |
b |
|ab| |
ab |
a |
a |
b |
b |
ab |
ab |
又由集合中元素的互異性,故x的所有值組成的集合為{-1,3}
故選D.