Question

9、一個(gè)數(shù)等于它的相反數(shù)的絕對(duì)值，則這個(gè)數(shù)是（　�。�

A、正數(shù)和零

B、負(fù)數(shù)或零

C、一切正數(shù)

D、所有負(fù)數(shù)

Answer 1

分析：根據(jù)絕對(duì)值的性質(zhì)解答即可．

解答：解：因?yàn)榛�為相反�?shù)的兩個(gè)數(shù)的絕對(duì)值相等，所以一個(gè)數(shù)等于它的相反數(shù)的絕對(duì)值，即這個(gè)數(shù)的絕對(duì)值等于它本身；
又因?yàn)檎龜?shù)和零的絕對(duì)值等于它本身，故一個(gè)數(shù)等于它的相反數(shù)的絕對(duì)值，則這個(gè)數(shù)是正數(shù)和零．
故選A．

點(diǎn)評(píng)：此題考查了絕對(duì)值的性質(zhì)，要求掌握絕對(duì)值的性質(zhì)及其定義，并能熟練運(yùn)用到實(shí)際當(dāng)中．
規(guī)律總結(jié)：一個(gè)正數(shù)的絕對(duì)值是它本身；一個(gè)負(fù)數(shù)的絕對(duì)值是它的相反數(shù)；0的絕對(duì)值是0．