7993 /www/nrich/html/content/id/7993/ 1 0000-00-00T00:00:00 <mdoxml version="1.0"><p>We know a, b and c are real numbers, abc is negative and (a-1)(b-1)(c-1) is positive. What can we deduce about a, b and c?</p></mdoxml> 2 3 0 0 1 1 0 We know a, b and c are real numbers, abc is negative and (a-1)(b-1)(c-1) is positive. What can we deduce about a, b and c?