SOLUTION: Question: Solve 1/4=8^5x-4 POssible Four Answers: (1) 2/15 (2) 2/3 (3) 2/5 (4) 14/15

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Question 29870: Question: Solve 1/4=8^5x-4
POssible Four Answers:
(1) 2/15
(2) 2/3
(3) 2/5
(4) 14/15
Answer by sdmmadam@yahoo.com(530) About Me  (Show Source):
You can put this solution on YOUR website!
1/4=8^5x-4
That ia 1/(2^2) = (2^3)^(5x-4)
2^(-2) = 2^[3(5x-4)] (using 1/(a^m)=(a)^(-m) and (a^m)^n = (a)^(mn) )
(-2) = 3(5x-4) (when bases are the same the powers are equal)
-2 = 15x-12
-2+12 = 15x
10 =15x
That is 15x = 10
Dividing by 15
x = 10/15 = 2X5/3X5 = 2/3 (canceling 5)
Answer: 2/3
Which is your choice 2)