(1)∵y=x2-5x-6=(x- 5 2 )2- 49 4 ,∴y=x2-5x-6单调增区间为[ 5 2 ,+∞);单调减区间为(-∞, 5 2 ].(2)∵y=9-x2,x∈[-2,3],∴y=9-x2单调增区间为[-2,0];单调减区间为(0,3].(3)∵y=- 2 x ,∴其单调增区间为(-∞,0),(0,+∞).(4)∵y=|x+1|,∴其单调增区间为[-1,+∞);单调减区间为[-∞,-1].