若點(diǎn)A(-n,2)與B(-3,m-1)關(guān)于原點(diǎn)對(duì)稱,則m+n等于________.
-4
分析:根據(jù)關(guān)于原點(diǎn)對(duì)稱的點(diǎn)的橫坐標(biāo)與縱坐標(biāo)都互為相反數(shù)解答.
解答:∵點(diǎn)A(-n,2)與B(-3,m-1)關(guān)于原點(diǎn)對(duì)稱,
∴-n=3,m-1=-2,
解得n=-3,m=-1,
∴m+n=-1+(-3)=-4.
故答案為:-4.
點(diǎn)評(píng):本題考查了關(guān)于原點(diǎn)對(duì)稱的點(diǎn)的坐標(biāo),熟記關(guān)于原點(diǎn)對(duì)稱的點(diǎn)的橫坐標(biāo)與縱坐標(biāo)都互為相反數(shù)是解題的關(guān)鍵.