4^(12-4x)=256 precalc?
I'm sure the answer is 2. But I got that by just looking what 4 is raised to to get 256.
My teacher wants me to show a different kind of work- Including logs.
I can't figure out how to get X alone. Help?
Answers & Comments
256 = 4^ 4
so
4^(12-4x) = 4^4
==> 12 - 4x = 4
==> 4x = 8
==> x = 2
(12-4x) log4 = log 256
12-4x = log256 /log4 =4
12-4x =4 so x=2
4^(12 - 4x) = 256
4^(4 * (3 - x)) = 256
256^(3 - x) = 256
(3 - x) * log(256) = log(256)
3 * log(256) - x * log(256) = log(256)
2 * log(256) = x * log(256)
2 = x