
Dear Professors (and others)  this is a nifty question, which has given me some insights beyond its usefulness as a direct readout of the solution intervals for appropriate inequalities. I was, however, unable to apply it to exercise 36 of the same section, as I reach an impasse at x(x1)(x+1) < 0, since one cannot divide by a variable without knowing whether that variable is <0 or >0. Is there a trick I'm missing (or even something obvious I should be seeing)? A tip would be great. Thanks, Bob Simons
