log equations?

0 ⤊

solve each log. equation:

log5 x = -3

How do I solve this? Can you please help, I am so lost!

Thanks for any help,

Jennifer

2007-05-07 11:40:16 · 3 answers · asked by jennifermlayne 2 in Science & Mathematics ➔ Mathematics

rethink it as an exponential equation. remember the log is the exponent.

log[5] x = -3 means 5^(-3) = x, so x = 1/125

2007-05-07 11:45:36 · answer #1 · answered by Philo 7 · 0⤊ 1⤋

If this is a log base 10 then you:

10^log5x = 10^-3

(10^log cancels each other out because they are opposites)

5x = 0.001

x = 0.0002

2007-05-07 18:46:57 · answer #2 · answered by stacy 2 · 0⤊ 0⤋

log(5x) = -3

log(5x) = log(10^(-3))

5x = 10^(-3)

x = 10^(-3) / 5

x = 2x10^(-4) = 0.0002

2007-05-07 18:46:51 · answer #3 · answered by Dimos F 4 · 0⤊ 0⤋