Question

What is the value of x in the following equation 1/5x=5^8 A)-8 B) 8 C)40 D)-40

Answer 1

The correct question is
What is the value of x in the following equation (1/5)^x=5^8 

Applying logarithms both members
log(1/5)^x=log(5^8) 
x*log(1/5)=8*log(5)
x=8*log(5)/log(1/5)

we know that
log (1/5)----> log (1)-log (5)----> 0-log (5)-----> -log (5)
so
x=8*log(5)/-log (5)------> x=-8

the answer is
-8