Question

plz solve this problem

Answer 1

Logarithm,

We have,
10^2y = 25

Have to find the value of 10^-y

By applying log we get,
log10^2y = log25
or, log10^2y = log(5)²
or, 2ylog10 = 2Log5 [eliminating 2 from the equation]
or, ylog10 = log5
or, -log10^-y = log5 [as -(-y)log10 = ylog10]
or, -log10^-y = log5
or, log10^-y = -log5
or, log10^-y = log5^-1
or, 10^-y = 5^-1 [eliminating log from the equation]
or, 10^-y = 1/5

That's it
Hope it helped (｡ŏ﹏ŏ)

Answer 2

Given,
10^2y = 25 .

Applying logarithm on both sides,.

2y log10 = 2 log5

ylog10 = log5

- log 10^ -y = log5

log 10 ^ -y = -log5

log 10 ^ -y = log 5 ^ -1

Cancelling logarithm on both sides,

10 ^ -y = 5 ^ -1

10^-y = 1/5 .

Hope helped !