题目

Sandra Bullock turned 51 last month. But because she looks exactly the same as she did in Miss Congeniality, a movie filmed back in the 20th century, everyone calls her “ageless.” Bullock is just one of a number of stars in their 40s and 50s who’ve had birthdays recently but have not gotten older, unlike the rest of us in their age group. Take Halle Berry. One website put a photo of her 20 years ago next to one of the newly 49-year-old Berry and dared us to choose which was which. “This Is What 49 Looks Like,” it said. Seriously, if that’s what 49 looks like, I must be 71. 5．设y=f（x）是二次函数，且f（0）=8及f（x+1）-f（x）=-2x+1（1）求f（x）的解析式（2）求函数y=log3f（x）的值域．