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Math

Math Snap

PROBLEM

Identify the solution set of 3ln4=2lnx3 \ln 4=2 \ln x.
\{6\}
{8,8}\{-8,8\}
{8}\{8\}

STEP 1

What is this asking?
We need to find the value of xx that makes the equation 3ln4=2lnx3 \ln 4 = 2 \ln x true.
Watch out!
Remember the logarithm power rule: nlna=ln(an)n \ln a = \ln (a^n).
Don't forget to check your answer!

STEP 2

1. Rewrite the equation using the power rule.
2. Simplify both sides.
3. Isolate xx.
4. Check the solution.

STEP 3

We have 3ln43 \ln 4.
Using the power rule of logarithms, which says nlna=ln(an)n \ln a = \ln (a^n), we can rewrite this as ln(43)\ln (4^3).
Why? Because it helps simplify the equation and brings the coefficient of the logarithm up as an exponent.
This makes it easier to compare the arguments of the logarithms.

STEP 4

We have 2lnx2 \ln x.
Using the power rule, we can rewrite this as ln(x2)\ln (x^2).
This helps us get closer to solving for xx.

STEP 5

Now, our equation looks like this: ln(43)=ln(x2)\ln (4^3) = \ln (x^2).
Much better!

STEP 6

We have ln(43)\ln (4^3).
Since 43=444=644^3 = 4 \cdot 4 \cdot 4 = 64, we have ln64\ln 64.

STEP 7

Our equation now looks like this: ln64=ln(x2)\ln 64 = \ln (x^2).
Almost there!

STEP 8

Since ln64=ln(x2)\ln 64 = \ln (x^2), we know that the arguments of the logarithms must be equal.
This means 64=x264 = x^2.

STEP 9

To solve 64=x264 = x^2 for xx, we take the square root of both sides.
This gives us x=±64x = \pm \sqrt{64}, which simplifies to x=±8x = \pm 8.
So, xx can be either 8 or -8.

STEP 10

If x=8x = 8, our original equation becomes 3ln4=2ln83 \ln 4 = 2 \ln 8.
Using the power rule, this simplifies to ln(43)=ln(82)\ln (4^3) = \ln (8^2), or ln64=ln64\ln 64 = \ln 64.
This is true!

STEP 11

If x=8x = -8, our original equation becomes 3ln4=2ln(8)3 \ln 4 = 2 \ln (-8).
Uh oh!
We can't take the logarithm of a negative number!
So, 8-8 is not a valid solution.

SOLUTION

The solution set is {8}\{8\}.

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