22.设二次函数f(x)=x2+(a−1)x+af(x)=x^{2}+(a-1)x+af(x)=x2+(a−1)x+a.(1)若该二次函数无零点,求实数aaa的取值范围;(2)方程f(x)=0f(x)=0f(x)=0的两根为x1x_{1}x1,x2x_{2}x2,若x1∈(−1,0)x_{1}\in (-1,0)x1∈(−1,0),x2∈(1,2)x_{2}\in (1,2)x2∈(1,2),求实数aaa的取值范围.