Solving For X

tristatefabricatorsinc said:
Solve for X: e^x-2 = 11
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The equation doesn't contain "X". Did you mean "solve for x"...? (Mathematically, these are two different variables and, yes, you will sometimes be dealing with both cases of a letter in a single exercise. Clarity will be important.)

Please note: The answer will vary, depending upon whether you mean "e<sup>x</sup> - 2 = 11", as posted, or something like "e<sup>x - 2</sup> = 11".

Thank you.

Eliz.
 
tristatefabricatorsinc said:
I apologize
solve for x:
e ^x-2 = 11
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STILL not clear, trista;
e^x - 2 = 11, so e^x = 13
OR
e^(x - 2) = 11

:?:
 
As before, take natural logs (the log base e) of both sides.
 
Have you met the "logarithm"?

e^(x - 2) = 11

ln(e^(x - 2)) = ln(11)

Properties of Logs

(x-2)*ln(e) = ln(11)

Properties of Logs

(x-2)*(1) = ln(11)
(x-2) = ln(11)

Now what?
 
tristatefabricatorsinc said:
x = ln(13)
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No. Very bad. No relationship to the correct answer.

I take the answer to my question to be "No." Did you just miss your introduction to logarithms or did you fail to read the list of prerequisites for the class you are in?

It may be time to back up a step or two and take a better crack at it on the next pass.
 
e^x - 2 = 11
add 2 to both sides
e^x = 13
now take the natural log of both sides
ln (e^x) = ln(13)
x = ln(13)

how is x = ln(13) not the answer?

if you plug in e^(ln(13)-2) into the calculator, it comes out as 11, is that not correct?
 
tristatefabricatorsinc said:
if you plug in e^(ln(13)-2) into the calculator, it comes out as 11
Click to expand...
Only if your calculator misunderstood you to mean "e<sup>ln(13)</sup> - 2".

Eliz.
 
tristatefabricatorsinc said:
e^x - 2 = 11 is that not correct?
Click to expand...
e^(x - 2) = 11

First, you must make up your mind what the problem statement is.
 
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