SOLUTION: Algebraically solve: a)sq root 125^x = (25)(5^-2x) b)4^(-2x+1)=sq root8 I got 1/8 but was told that I was wrong ?!?! c)3x^-3 = 81 ???

Algebra ->  Exponents -> SOLUTION: Algebraically solve: a)sq root 125^x = (25)(5^-2x) b)4^(-2x+1)=sq root8 I got 1/8 but was told that I was wrong ?!?! c)3x^-3 = 81 ???      Log On


   

Question 279564: Algebraically solve:
a)sq root 125^x = (25)(5^-2x)
b)4^(-2x+1)=sq root8 I got 1/8 but was told that I was wrong ?!?!
c)3x^-3 = 81 ???
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Algebraically solve:
a)sq root 125^x = (25)(5^-2x)
If it's sqrt%28125%5Ex%29, then
= 5%5Ex%2Asqrt%285%5Ex%29
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or = 5%5E%283x%2F2%29 (5^(3x/2)), hard to see it
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b)4^(-2x+1)=sq root8 I got 1/8 but was told that I was wrong ?!?!
4%5E%281-2x%29+=+sqrt%288%29
2%5E%282-4x%29+=+2%5E%283%2F2%29
2-4x = 3/2
4-8x = 3
8x = 1
x = 1/8
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Check:
4^(1- 1/4) = sqrt(8)
4^(3/4) = 2^(3/2) = sqrt(8)
It is 1/8, who says it's wrong?
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c)3x^-3 = 81 ???
x^-3 = 27
x^-1 = 3
x = 1/3