85. From three relative (positive and negative) numbers, all possible products of two are formed. What can be the signs of these three products? What can be said about the number of positive products in each case?
85. Or all three numbers have the same sign: then all three products of these numbers, taken in pairs, are positive; or one number has a sign opposite to the other two: then one product is positive, two are negative. Thus, the number of positive products can be either 3 or 1. (Construct the corresponding table).