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5^(z+1)/3 = 25^z

 

WHAT IS Z??? PLEASE HELP!

 Feb 29, 2016
 #1
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Solve for z over the real numbers:
5^(z+1)/3 = 25^z

Take the natural logarithm of both sides and use the identities log(a b) = log(a)+log(b) and log(a^b) = b log(a):
log(5) (z+1)-log(3) = 2 log(5) z

Expand out terms of the left hand side:
log(5) z-log(3)+log(5) = 2 log(5) z

Subtract 2 z log(5)-log(3)+log(5) from both sides:
-(log(5) z) = log(3)-log(5)

Divide both sides by -log(5):
Answer: |  z = 1-(log(3))/(log(5))=0.317393805......

 Feb 29, 2016
 #2
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I'm assuming this is :

 

5^[(z+1)/3] = 25^z      if so, we can write

 

5^[ (z + 1) / 3 ]  = (5^2)^z

 

5^[ (z + 1)/ 3 ]   = 5^(2z)      since the bases are the same, we can solve for the exponents

 

[ z + 1 ] / 3   =  2z       multiply both sides by 3

 

z + 1  = 6z       subtract z  from both sides

 

1 = 5z             divide both sides by 5

 

1/5   = z

 

 

cool cool cool

 Feb 29, 2016

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