解不等式 2x - a > 3 得:x > (a + 3)/2
解不等式 x + b < 2得:x < b + 2
因为不等式组的解集是:- 1 < x < 1
所以有:(a + 3)/2 = - 1,解得:a = - 5
b + 2 = 1 ,解得:b = -1
因此:ab = (-5)×(-1) = 6