——Thank you so much for your present. It's really nice.——____________
A:Please don't say so.
B:It's not so good, I think.
C:No, thanks.
D:I'm glad you like it.
在( )里填上合适的数。
89− (____) =79 (____) +211=711 1720+ (____)=1
1− (____) =28 57− (____)= 27 (____) +25=45
413+ (____) =113+713 1−110= (____) +210
—Don't worry. There is still time left.
己知函数f(x)=loga(x+1),g(x)=2loga(2x+t)(t∈R),a>0,且a≠1.
(1)若1是关于x的方程f(x)﹣g(x)=0的一个解,求t的值;
(2)当0<a<1且t=﹣1时,解不等式f(x)≤g(x);
(3)若函数F(x)=af(x)+tx2﹣2t+1在区间(﹣1,2上有零点,求t的取值范围.