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Posted by **Tristan** on Tuesday, September 14, 2010 at 7:12pm.

8(2^x-1)=64

- ALGEBRA 2 URGENT! PLEASE HELP! -
**Jen**, Tuesday, September 14, 2010 at 10:30pmSince 8^2=64, set 2^x-1=2, 2^1=2 so x-1=1, x=?

- ALGEBRA 2 URGENT! PLEASE HELP! -
**Henry**, Wednesday, September 15, 2010 at 6:42pmI'm assuming x-1 is the exponent.

8 * 2^(x-1) = 64,

2^3 * 2^(x-1) = 2^6,

Add the exponents on the left side:

3 + x - 1 = x + 2,

2^(x+2) = 2^6,

The exponent on both sides has the

same base(2). Therefore,

x + 2 = 6,

x = 4.

Check: substitute 4 for x in the given Eq:

8 * 2^(4-1) =

8 * 2^3 = 8 * 8 = 64.