1.數(shù)軸上A,B,C三個(gè)點(diǎn)對(duì)應(yīng)的數(shù)分別為a,b,x,且A,B到-1所對(duì)應(yīng)的點(diǎn)的距離都等于7,點(diǎn)B在點(diǎn)A的右側(cè),
(1)請(qǐng)?jiān)跀?shù)軸上表示點(diǎn)A,B位置,a=
,b=
;
(2)請(qǐng)用含x的代數(shù)式表示CB=
;
(3)若點(diǎn)C在點(diǎn)B的左側(cè),且CB=8,點(diǎn)A以每秒2個(gè)單位長度的速度沿?cái)?shù)軸向右運(yùn)動(dòng),當(dāng)AC=2AB且點(diǎn)A在B的左側(cè)時(shí),求點(diǎn)A移動(dòng)的時(shí)間.