对画线部分提问
Tom rode his motorbike to work yesterday and had a crash with a car. His motorbike was ________ and he was seriously ________.
已知f(x)= {22−x,x<2log3(x+1),x≥2 若对任意的x∈R,af2(x)≥4f(x)﹣1成立,则实数a的最小值为____.