at least 1 must be negative
if remember, 2 negatives multiplied together cancel
if we had 0 negatives, we would get positive
if we had 1 negative, we would get negative
if we had 2 negatives, we would get positive
if we had 3 negative, we would get negative
if we had 4 negatives, we would get positive
if we had 5 negative, we would get negative
if we had 6 negatives, we would get positive
so 1 or 3 or 5 must be negaitve