A:to prepare
B:to have prepared
C:having prepared
D:to be preparing
(Ⅰ)若方程f(x)﹣x=0有唯一实数根,求函数f(x)的解析式;
(Ⅱ)当a=1时,求函数f(x)在区间﹣1,2上的最大值与最小值;
(Ⅲ)当x≥2时,不等式f(x)≥2﹣a恒成立,求实数a的取值范围.
因式分解:ax2﹣7ax+6a=____ .