2.LOG5135 = 3 A= 12LOG2(3.25) LOG23 = 2B−23A A= 12LOG23 + LOG25 A= LOG...
2
.log
5
135 =
3
a
=
1
2
log
2
(3.25)
log
2
3 = 2b
−
2
3
a
a
=
1
2
log
2
3 + log
2
5
a
= log
4
75
Lại có:
b
= log
8
45
⇔
b
=
1
3
log
2
(9.5)
⇔
b
=
2
3
log
2
3 +
1
3
log
2
5
⇔
log
2
5 =
4
3
a
−
b
.
3 2b
−
2
3
a
+
4
3
a
−
b
Do đó:
log
√
3
25
135 =
3
4
2