Question

2^x-1=128 show work pls! thank u :)

Answer 1

Hello from MrBillDoesMath!

Answer:

Take you pick below!   (either x 8 or x = 7.01, approx, depending how the question is interpreted)

Discussion:

Interpretation 1

If the question is   2^(x -1)  = 128, then as 2^7 = 128,

x-1 = 7 so x = 8

Interpretation 2

If the question is (2^x -1) = 128, then..

2^x  = 128 + 1 = 129  =>

log(2^x) = log(129) =>

xlog(2) = log(129) =>

x = log (129) / log2 = 7.01

Regards,  

MrB