Question

Вычислить log(1/2) 28 -log(1/2) 7

Answer 1

$...=log_{\frac{1}{2}}(2^2\cdot 7)-log_{\frac{1}{2}}7=log_{2^{-1}}2^2+\log_{\frac{1}{2}}7-log_{\frac{1}{2}}7=-log_22^2=-2$

Answer 2

$log _{ \frac{1}{2} } 28-log _{ \frac{1}{2} }7=log _{ \frac{1}{2} } ( \frac{28}{7} )=log _{ \frac{1}{2} } 4=log _{2 ^{-1} } 2 ^{2} = \frac{2}{-1} log _{2} 2= \\ =-2*1=-2$