Question

Jika 2log3=a dan 3log7=b ,nyatakan bentuk bentuk berikut dalam a dan b! a.2log42 b.0,5 log 147?

Answer 1

2 log 3 = a
3 log 7 = b
2 log 7 = ab

a) 2 log 42 ?
= 2 log 42
= 2 log 7 . 2 . 3
= 2 log 7 + 2 log 2 + 2 log 3
= ab + 1 + a

b) 0,5 log 147
= 0,5 log 147
= 2^-1 log 147
= -1 . 2 log 147
= -1 ( 2 log 3 . 7 . 7 )
= -1 ( 2 log 3 + 2 log 7 + 2 log 7 )
= -1 ( a + ab + ab )
= -a - 2ab
= a ( -1 - 2b )