Treat both < signs as equals signs so instead of just subtract 1 from 2 sides you must do it three times.
-3 < 2x +1 <= 3 ----> -3 - 1 < 2x +1 - 1 <= 3 - 1 which becomes -4< 2x <= 2
divide by 2 in all three zones. -4/2 < 2x/2 < 2/2 which becomes -2 < x <= 1 so our answer is between -2 and 1 including 1.
Interval notation: (-2, 1]
Anayeli H.
09/20/13