c) 198519851985.198719871987/ 19861986.198619861986
Giải thích
c) Ta có: 198519851985.198719871987198619861986.198619861986=1985.100010001.1987.1000100011986.100010001.1986.100010001=1985.198719862
=(1986−1)(1986+1)19862=19862−119862<1
c) Ta có: 198519851985.198719871987198619861986.198619861986=1985.100010001.1987.1000100011986.100010001.1986.100010001=1985.198719862
=(1986−1)(1986+1)19862=19862−119862<1