I'm not sure exactly what you're asking for, but it appears to be either (4^5)* x = 15 or 4^(5x) = 15
Oh well....doesn't matter......I'll do both and you can take your choice
First.......
(4^5)* x = 15
(1024) * x =15
solving for x by dividing both sides by 1024, we have
x =
15 / 1024
Second................. (I think this is the one you're really interested in)
4^(5x) = 15
Take the log of both sides
log(4)^(5x) = log(15)
By the property of logs we can write
(5x)*log(4) = log (15)
Divide by log(4) on both sides
(5x) = log (15) / log (4)
Now divide by 5 on both sides
x =
log(15)/(5*log(4))
And there you go..........
+128474 
