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August 20, 2014

August 20, 2014

Posted by **Lucy** on Monday, March 17, 2008 at 6:28pm.

(1/81)^t=243^t-2

The book states to get the same base but I don't understand.

Thanks for any help.

- Algebra II -
**Reiny**, Monday, March 17, 2008 at 9:31pmthe key is to recognize

both 81 and 243 as powers of 3

81 = 3^4 and 243 = 3^5

so (1/81)^t=243^t-2

(3^-4)^t = (3^5)^(t-2)

3^(-4t) = 3^(5t-10)

then -4t = 5t - 10

-9t=-10

t=10/9

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