Question

logarithmic equation, solve for x:
43 = 11 ln (4x+5)
(my work in reply)

Answer 1

since 43/11 = ln(4x+5), e^(43/11) = 4x+5
so,
49.9=4x+5
44.9=4x
x=11.2

Answer 2

My answer isn't correct. What am I doing wrong?
\[43 = 11 \ln(4x+5)\]
\[e^{43} = 11(4x+5)\]
\[e^{43} = 44x + 55\]
\[e^{43} - 55 = 44x\]
\[x = \frac{ e^{43}-55 }{ 44 }\]

Answer 3

you need to divide by 11 first.

Answer 4

Answered before I finished typing out my work, haha.
That was it. ok, so I need to remember to get the log by itself first?
I got:
\[x=\frac{ e^{43/11} - 5 }{ 4 } \approx 11.2\]
Thank you!

Answer 5

yup. good job