已知f(x)=满足f(a)=3,则f(a-5)的值为( )(A) (B) (C)log23(D)1
问题详情：已知f(x)=满足f(a)=3,则f(a-5)的值为()(A) (B) (C)log23(D)1【回答】A解析:当a≤3时,f(a)=2a-3+1=3⇒a=4>3,不合题设;当a>3时,f(a)=log2(a+1)=3⇒a=7>3,成立,所以f(a-5)=f(2)=22-3+1=.故选A.知识点：基...
问题详情：已知f(x)=满足f(a)=3,则f(a-5)的值为()(A) (B) (C)log23(D)1【回答】A解析:当a≤3时,f(a)=2a-3+1=3⇒a=4>3,不合题设;当a>3时,f(a)=log2(a+1)=3⇒a=7>3,成立,所以f(a-5)=f(2)=22-3+1=.故选A.知识点：基...