Posted by Tristan on Tuesday, September 14, 2010 at 7:12pm.
Since 8^2=64, set 2^x-1=2, 2^1=2 so x-1=1, x=?
I'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.