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anonymous

  • 5 years ago

I need someone to just check my work... and tell me where I went wrong?

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  1. anonymous
    • 5 years ago
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    The problem is 2^x+3=5x

  2. anonymous
    • 5 years ago
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    What did you get?

  3. anonymous
    • 5 years ago
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    next step: (x+3)ln2/xln2=xln5/xln2

  4. anonymous
    • 5 years ago
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    I got 2.269

  5. anonymous
    • 5 years ago
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    next step: x+3/x=ln5/ln2

  6. anonymous
    • 5 years ago
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    next step: x+3/x=2.322/1

  7. anonymous
    • 5 years ago
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    Something is wrong. Was the original equation \[2^{x+3} = 5^x\] ?

  8. anonymous
    • 5 years ago
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    no 2^ x+3=5x

  9. anonymous
    • 5 years ago
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    Ok, then when you take the ln of both sides you'll have ln5 + lnx on the right hand side of the equal.

  10. anonymous
    • 5 years ago
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    Which is gonna be a pain.

  11. anonymous
    • 5 years ago
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    Was it \[2^{x+3} = 5x\] ?

  12. anonymous
    • 5 years ago
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    Yes

  13. anonymous
    • 5 years ago
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    Yeah, there's no good way to simplify that. I suspect you have the question wrong.

  14. anonymous
    • 5 years ago
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    Best you can do is something like \[x(ln 2) - lnx = ln(5/3)\]

  15. anonymous
    • 5 years ago
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    Err wait, that should be ln(5/8) on the right side.

  16. anonymous
    • 5 years ago
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    My teacher told us to set each side to the natural... which gave me: (x+3)ln2=xln5

  17. anonymous
    • 5 years ago
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    Then I needed to get everything canceled out by cross multiplying... so I divided both sides by xln2

  18. anonymous
    • 5 years ago
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    That's not right though. Unless you had 5^x on the right side originally.

  19. anonymous
    • 5 years ago
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    Was it \(5x\) or \(5^x\)

  20. anonymous
    • 5 years ago
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    the second one... I just looked in my book. Im so sorry

  21. anonymous
    • 5 years ago
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    Ok good.

  22. anonymous
    • 5 years ago
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    So yeah that's right. take the ln of both sides (or any log really)

  23. anonymous
    • 5 years ago
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    Then solve for x. Don't plug anything into your calculator until you have something where x = something that has no x

  24. anonymous
    • 5 years ago
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    (x+3)ln2=xln5 is correct for starting out

  25. anonymous
    • 5 years ago
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    ok... then what do I need to divide both sides by? she taught us to cross multiply? I divided both sides by xln2 just to cancel out. And I ended up with x+3/x=ln5/ln2

  26. anonymous
    • 5 years ago
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    Get all terms with an x on one side.

  27. anonymous
    • 5 years ago
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    Or that. Cross multiplying works fine

  28. anonymous
    • 5 years ago
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    I usually multiply out products, but you don't need to here

  29. anonymous
    • 5 years ago
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    Just be sure that you do (x+3)/x = ln5/ln2

  30. anonymous
    • 5 years ago
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    Not just the 3.

  31. anonymous
    • 5 years ago
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    I did and I got: x+3/x= 2.322/1

  32. anonymous
    • 5 years ago
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    then: x+3=2.322x

  33. anonymous
    • 5 years ago
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    Don't plug things in.

  34. anonymous
    • 5 years ago
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    Keep solving the equation until you have x by itself. x = something that has no x.

  35. anonymous
    • 5 years ago
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    Then plug in

  36. anonymous
    • 5 years ago
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    Im not sure what/where.I am attempting to get x by itself? I thought that is what I was doing?

  37. anonymous
    • 5 years ago
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    I think cross multiplying is just making this harder.

  38. anonymous
    • 5 years ago
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    I just got a different answer of -4.425

  39. anonymous
    • 5 years ago
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    Lets back up.

  40. anonymous
    • 5 years ago
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    Ok..Im just trying to follow the instructions. But Im willing to try anything at this point

  41. anonymous
    • 5 years ago
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    \[(x+3)ln2=xln5\] \[x(ln2)+3(ln2)=x(ln5)\] \[x(ln2)- x(ln5)= - 3(ln2)\] \[x[(ln2)- (ln5)]= - 3(ln2)\] \[x= \frac{- 3(ln2)}{(ln2)- (ln5)}\]

  42. anonymous
    • 5 years ago
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    Thanks for your time.. I appreciate it. I will continue to search for the answer. I need to learn it the way she taught us, Im afraid I will be jumping the gun and not learning anything... thanks so much.

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