A logarithm?

1 ⤊

I'm stuck with Evaluate log 15 + log 20 - log 12. All these logs are to base 5. i have tried and come out with different answers than the one stated on the answer sheet. thanks.

I would also like to thank guys who helped me on cubic polynomials.

2007-06-06 07:26:46 · 3 answers · asked by markuk1990 1 in Science & Mathematics ➔ Mathematics

3 answers

log 15 + log 20 - log 12
= log(15*20/12)
= log25
= 2, if the base is 5.

2007-06-06 07:31:33 · answer #1 · answered by sahsjing 7 · 1⤊ 0⤋

In following solution "log" means log base 5:-
log 15 + log 20 - log 12
= log (15 x 20 / 12)
= log 25
= 2

2007-06-06 15:36:35 · answer #2 · answered by Como 7 · 0⤊ 0⤋

log(15x20/12) = log(25)

2007-06-06 14:34:14 · answer #3 · answered by what? 7 · 0⤊ 0⤋