SOLUTION: Solve using exponent laws: a) 9^4x-1=27(81^x-1) b) 7^2x+1= index of 3radical sign with 49 inside of it thanks :) Have been trying to solve these all night :)

Algebra ->  Exponents -> SOLUTION: Solve using exponent laws: a) 9^4x-1=27(81^x-1) b) 7^2x+1= index of 3radical sign with 49 inside of it thanks :) Have been trying to solve these all night :)      Log On


   

Question 924766: Solve using exponent laws:
a) 9^4x-1=27(81^x-1)
b) 7^2x+1= index of 3radical sign with 49 inside of it
thanks :) Have been trying to solve these all night :)
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Solve using exponent laws:
a) 9^4x-1=27(81^x-1)
If the exponent of 9 is 4x-1, and the exponent of 81 is x-1:
9 = 3^2
27 = 3^3
--> 3%5E%282%2A%284x-1%29%29+=+27%2A%283%5E%284%2A%28x-1%29%29%29
3%5E%288x-2%29+=+3%5E3%2A%283%5E%284x-4%29%29
3%5E%288x-2%29+=+%283%5E%284x-1%29%29
8x-2 = 4x-1
4x = 1
x = 1/4
==================
b) 7^2x+1= index of 3radical sign with 49 inside of it
If you mean:
7%5E%282x%2B1%29+=+root%283%2C49%29
7%5E%282x%2B1%29+=+7%5E%282%2F3%29
2x+1 = 2/3
x = -1/6
===================
Put parentheses around the exponents to eliminate ambiguity. They're free.