Posted by **Sara** on Monday, January 9, 2012 at 6:15pm.

solve the following equation show all work log4(x-4)= -1.

- precalculus -
**Reiny**, Monday, January 9, 2012 at 6:21pm
by definition:

log_{4} (x-4) = -1

is equivalent to

x-4 = 4^-1

x-4 = 1/4

x = 1/4 - 4

= -15/4

so we would have log (-3/4-4)

but we cannot take the log of a negative, so ....

no solution.

- precalculus -
**Steve**, Tuesday, January 10, 2012 at 12:22am
log takes on all real values for its range. So, something's wrong here.

x - 4 = 1/4

x = 1/4 + 4

x = 17/4

log_{4}(17/4 - 4) = log_{4}(1/4) = -1

## Answer this Question

## Related Questions

- Logarithms - Solve log4 x + log4(x-2)=log4(15) I know how do the example in my ...
- precalculus - solve the following exponential equation. show all work. 4^(4x+2...
- precalculus - write the expression as a sum or difference of logarithms. express...
- Algebra II - Solve, round to four decimal places if necessary: log4(x-9)=2 ...
- Trig/Pre-Calc - Could someone please help me on this problem. I'm really ...
- Algebra 2 - Simplify: 1. 2log10^5+log10^4 2. 2log3^6-log3^4 3. log4^40-log4^5 4...
- precalculus - solve the exponential equation express in exact form only show all...
- Math Algebra 2 - #4. Express the logarithm in terms of log2M and log2N: log2 1/...
- math - 2. Simplify. Please be sure to show all of your work. -3(-9) – |-5 – 3 3...
- math - Solve the equation algebraically. Round the result to three decimal ...