How do you write the equation log_(1/5) (25)=-2 in exponential form?

1 Answer
Oct 8, 2016

log_(1/5)25 = -2 " " hArr " " (1/5)^-2 = 25

Explanation:

Recall: " "log_a b = c " "hArr " " a^c = b

The two forms are interchangeable and give the same information, just with a different subject.

Remember: "The base stays the base and the other two swop around"

log_10 100 = 2" " asks the question:

"What power of 10 will give 100?" Or

"What index will make 10 into 100?" The answer is 2.

10^2 = 100" " states that 10 raised to the power of 2 will give the answer 100.

log_(1/5)25 = -2 " " hArr " " (1/5)^-2 = 25

Let's check:

(1/5)^-2 = (5/1)^2 =25