Identify the solution set of 6 ln e = eln 2x {2} {3} {6}
The Correct Answer and Explanation is:
To solve the equation: 6lne=eln2×6 \ln e = e^{\ln 2x}
Step 1: Simplify the left side
We use the identity: lne=1\ln e = 1
So, 6lne=6⋅1=66 \ln e = 6 \cdot 1 = 6
Step 2: Simplify the right side
Use the identity: elna=a, for a>0e^{\ln a} = a, \text{ for } a > 0
So: eln2x=2xe^{\ln 2x} = 2x
Step 3: Solve the equation
Now the equation is: 6=2×6 = 2x
Divide both sides by 2: x=3x = 3
Step 4: Check domain restrictions
Since we used ln2x\ln 2x, and logarithms are only defined for positive arguments, we must have: 2x>0⇒x>02x > 0 \Rightarrow x > 0
Our solution x=3x = 3 satisfies this condition.
✅ Final Answer:
The solution set is {3}\{3\}.
📘 Explanation
The given equation is 6lne=eln2×6 \ln e = e^{\ln 2x}. To find the solution, we simplify both sides using logarithmic and exponential identities. The natural logarithm of ee, or lne\ln e, equals 1, so the left-hand side simplifies to 66.
On the right-hand side, we see eln2xe^{\ln 2x}, which seems complicated at first glance. However, we apply a useful identity from logarithmic and exponential functions: for any positive real number aa, elna=ae^{\ln a} = a. This is because exponentiation and logarithms are inverse operations.
Applying this identity, eln2x=2xe^{\ln 2x} = 2x, as long as 2x>02x > 0, meaning x>0x > 0. This is important because the logarithm is only defined for positive arguments, so 2x2x must be positive.
So now, our simplified equation is: 6=2×6 = 2x
To isolate xx, divide both sides by 2: x=3x = 3
Finally, we confirm that this value satisfies all domain requirements — specifically, x=3>0x = 3 > 0, so 2x=6>02x = 6 > 0, and ln2x\ln 2x is defined.
Thus, the only valid solution is x=3x = 3, and the solution set is {3}\{3\}. The other options ({2}, {6}) do not satisfy the equation.
