He is looking forward to ____ (go) cycling.
— Mom, I was the first to reach the top of the mountain.— Good job, Charlie. I'm ______ of you.
(Ⅰ)若f(x)=2,求x的值;
(Ⅱ)若2tf(2t)+mf(t)≥0对于t∈1,2恒成立,求实数m的取值范围.
化简:ab-1+b-aa2-1=____ .