1) log1/4((√17+1)/1/(√17-1))=log1/4(16)=-2
2) log9(1/7)+log9(21)-log9(1/27)=log9(3)-log9(1/27)=log9(81)=2
3) log1/4(√2/2)= 1/4
4) log0.2(16)-4log0.2(10)=log0.2(16)-log0.2(10000)=log0.2(16/10000)=log0.2(1/625)=4
5) log5(128)/log5(4)=log4(128)=7/2
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дальше всё по св-вам во вложении!
