已知集合A={x│ax的平方+x+2=0,a∈R},若A中至多有1个元素,则a的取值范围是?已知集合-3∈{a-3,2a-1,a的平方+1},求实数a的值.设A表示集合{2,3,a的平方+2a+3},B表示集合{│a+3│,2},已知5∈A且5不∈B,求a的值
(1)have,what,of,rules,your,do,you,in,class,kinds(2)pick,you'd,not,up,your,to,better,eat,bowl(3)walking,you,while,eat,down,street,shouldn't,the(连词成句)