Question

Tính:

a) \({\log _5}4 + {\log _5}\frac{1}{4}\);                                   

b) \({\log _2}28 - {\log _2}7\);     c) \(\log \sqrt {1000} \).

Answer 1

a) \(log_54+log_5\dfrac{1}{4}=log_5\left(4\cdot\dfrac{1}{4}\right)=log_51=0\)

b) \(log_228-log_27=log_2\left(28:7\right)=log_24=2\)