Tính: a) A=25^log 5 6 + 49 log 7 8 -3/3^1+ log 9 4 + 4 ^2-log 2 3+5 ^ log 125 27

Tính:

a)  A=25log56+49log78331+log94+42log23+5log12527;

b)  B=36log65+101log23log936log2(log242);

c)  C=log14(log34log23);

d) D = log4 2 . log6 4 . log8 6.

Trả lời
a) A=25log56+49log78331+log94+42log23+5log12527
=(52)log56+(72)log78333log94+424log23+5log53(33)=(5log56)2+(7log78)2333log32(22)+42(22)log23+5133log53
=62+82333log32+42(2log23)2+5log53=36+64332+4232+3=976+169+3=97979=9.

b) B=36log65+101log23log936log2(log242)
=(62)log65+1010log23log32(62)log2(log2214)=(6log65)2+1023122log36log2(log2218)
=52+53log36log2(18)=25+56log223=243=8.
c) C=log14(log34.log23)
=log22(log322log23)=12log2(2log32log23)=12log2(2log321log32)=12log22=12.
d) D = log4 2 . log6 4 . log8 6
=log42log44log46log46log48=log42log44log48
=log42log84=log84log42
=log82=log232=13log22=13.

Câu hỏi cùng chủ đề

Xem tất cả