Sunday

January 25, 2015

January 25, 2015

Posted by **Lee** on Sunday, November 14, 2010 at 2:33am.

2e^7x+4=4

(Round to four decimal places)

I tried solving this way

2e/2^7x+4=4/2

e^7x+4=2

ln e^7x+4=ln 2

7x+4=ln 2

7x+4-4=ln 2-4

7x=ln 2-4

7x/7=ln 2-4/7

x=ln 2-4/7

then I at a lose at this point.

What step should I perform next.

I know I'm suppose to use the calculator for the estimated solution, but I'm not coming up with the correct answer. Help!!!

- College Algebra -
**john**, Sunday, November 14, 2010 at 3:28am2e^7x +4=4

2e^7x=0

e^7x=0

ln1=0

so 7x=1

x=1/7

v.easy

- College Algebra -
**Lee**, Sunday, November 14, 2010 at 3:45amYes this would be very simple, except this is a logarithim equation. The answer you gave isn't correct either.

the e actually represect ln.

- LEE - College Algebra -
**Reiny**, Sunday, November 14, 2010 at 10:41amLee, the solution that John gave you is correct according to the way you typed the question.

I have a feeling you meant to type

2e^(7x+4) = 4

if so, then

e^(7x+4) = 2

take ln of both sides

ln(e^(7x+4)) = ln2

(7x+4)lne = ln2 , but lne = 1

7x+4 = ln2

7x = ln2 - 4

x = (ln2 - 4)/7 or appr. - .4724

- College Algebra -
**Lee**, Tuesday, November 16, 2010 at 10:46pmyou are correct. I understand it now. You are such a fantastic help :)

**Answer this Question**

**Related Questions**

pre-calculus - solve the exponential equation. express the solution in terms of ...

college algebra - Solve the exponential equation using logarithms. Give the ...

college algebra - Solve the exponential equation using logarithms. Give the ...

college - expects dividends paid to increase by 9.50 percent for the next two ...

Logs. - Can you please help me with the following log. problems? thanxs! Solve ...

algebra - Solve the equation algebraically. Round the result to three decimal ...

Calc - I am having trouble with these two problems for my Calc class. I have ...

calculus - solve the exponential equation. Express the solution in terms of ...

college algebra - solve the following exponential equation. (e^x-e^-x)/2=6 what ...

Calculus - Consider the function below. f(x) = [1-(4/x)]^x (a) Use a graph to ...