# Thread: Help make x the subject

1. ## Help make x the subject

I need help making x the subject of this formula y=2^(-x/t) i tried it on my calc using solve however it keeps giving me errors, can the above even been done?

thanks

sinners

2. try using log(log both sides):

taking into account
log a^b = b.log a

3. ## Does this help?

$y=2^{(-\frac{x}{t})}$

$\log_2y=-\frac{x}{t}$

$t\log_2y=-x$

$x=-t\log_2y$

$x=\log_2y^{-t}$

$x=\log_2\frac{1}{y^t}$