设全集U={(x,y)|x属于R,y属于R},A={(x,y)|2x-y+a>0},B={(x,y)|x+2y-b≤0},,则点P(1,4)属于A交(CUB)

问题描述:

设全集U={(x,y)|x属于R,y属于R},A={(x,y)|2x-y+a>0},B={(x,y)|x+2y-b≤0},,则点P(1,4)属于A交(CUB)
的充要条件是

b2