Đáp án:
Giải thích các bước giải: a) $$x\in ƯCLN(24,\hspace{0,1cm}36,\hspace{0,1cm}160,\hspace{0,1cm})=4$$
b) $$x\in ƯC(91,\hspace{0,1cm}26)=13, 26 thì\hspace{0,1cm}mới\hspace{0,1cm}đúng\hspace{0,1cm}điều\hspace{0,1cm}kiện\hspace{0,1cm}là\hspace{0,1cm}10<x<30$$
c) $$x\in BCNN(4,\hspace{0,1cm}7,\hspace{0,1cm}8)=56$$
d) $$x\in BC(12,\hspace{0,1cm}18)=36,\hspace{0,1cm}72,\hspace{0,1cm}108,\hspace{0,1cm}144,\hspace{0,1cm}180,\hspace{0,1cm}216\hspace{0,1cm}thì\hspace{0,1cm}mới\hspace{0,1cm}thõa\hspace{0,1cm}mãn\hspace{0,1cm}điều\hspace{0,1cm}kiện\hspace{0,1cm}như\hspace{0,1cm}đề\hspace{0,1cm}bài$$