Solve the logarithmic equation ln(3x−11)=ln(4+2x)

.(1 point)
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1 answer

To solve the logarithmic equation \( \ln(3x - 11) = \ln(4 + 2x) \), we can use the property of logarithms that states if \( \ln(a) = \ln(b) \), then \( a = b \).

So, we set the insides of the logarithms equal to each other:

\[ 3x - 11 = 4 + 2x \]

Now, we will isolate \( x \). First, subtract \( 2x \) from both sides:

\[ 3x - 2x - 11 = 4 \]

This simplifies to:

\[ x - 11 = 4 \]

Next, add 11 to both sides to solve for \( x \):

\[ x = 4 + 11 \]

\[ x = 15 \]

Now, we should check that this value does not make either logarithm undefined (the argument must be positive):

  1. For \( 3x - 11 \): \[ 3(15) - 11 = 45 - 11 = 34 > 0 \]

  2. For \( 4 + 2x \): \[ 4 + 2(15) = 4 + 30 = 34 > 0 \]

Both arguments are positive, so the solution is valid.

Thus, the solution to the equation is:

\[ \boxed{15} \]