How do you solve log_5(x+4)+log_5 8=log_5 64?

2 Answers
Oct 27, 2016

x=4

Explanation:

log_5 (x+4)+log_5 8 = log_5 8(x+4)

So 8(x+4)=64

x+4=8
x=4

Have you understood the rules of indices?
100 x1000= 100,000
10^2 x10^3=10^5
So in terms of the index numbers
2+3=5
Or
log_10 2+log_10 3=log_10 5
Which is the same as
log_10 (2 times 3) =log_10 5

Oct 29, 2016

Answer is x=4.

Explanation:

log_5 (x+4)+log_5 8=log_5 64
:.log(x+4)+log8=log64
:.log(x+4)+log2^3=log 2^6
:.log(x+4)+3log2=6log2
:.log(x+4)=3log2
:.log(x+4)=log2^3
:.x+4=8
:.x=4. (answer).