Xxx^2-x-2>0(x-2)(x+1)>0x<-1或X>2同理:x>配肢肢=g(x)得到-1<=x<饥缓=2所培世以f(x)= x^2+x+2,x<-1或X>2 x^2-x-2,-1<=x<=2然后画图值域就出来了
[-9/4,+∞)
-9/4到正无穷