解析：∵函数y=|x^2-x-6|=|(x-1/2)^2-25/4|
∴当(x-1/2)^2-25/4=0==>x1=-2,x2=3
即当x1=-2,x2=3时,函数y=0
当x1≠-2,x2≠3时,函数y>0
当x＞0时，y=（x-0.5）2+25/4 当x≤0时 y=（x+1/2）2+25/4 不对！应该为：∵函数y=|x^2-x-6|=|(x-1/2)^2-25/4|当(x-1/2)^2>25/4，即x<-2或x>3时，y=(x-1/2)^2-25/4当(x-1/2)^2<=25/4，即-2<=x<=3时，y=25/4-(x-1/2)^2