Solve Complex Logarithm Equation: log₂ₐ(e⁷) with Natural Logarithms
Question
Given 0<a , find X:
log2ae7(lna+ln4a)=log4x−log4x2+log4x+11
Video Solution
Step-by-Step Solution
To solve this problem, we'll follow these steps:
Step 1: Simplify the left side of the equation.
Step 2: Simplify the right side of the equation.
Step 3: Set the two sides equal and solve for X.
Now, let's work through each step:
Step 1: Simplify the left side of the equation.
Given: log2a(e7(lna+ln4a)).
Combine the logarithms: ln4a=ln4+lna.
Thus, lna+ln4a=lna+ln4+lna=2lna+ln4.
So, e7(2lna+ln4)=e7e2lnaeln4.
This simplifies to e7a2⋅4.
Therefore, the left side is: log2a(4a2e7).
Step 2: Simplify the right side of the equation.
Given: log4x−log4x2+log4x+11.
Combining using the quotient and power rules: log4x2x+log4x+11.
Further simplify: log4x(x+1)1.
Step 3: Set the two sides equal and solve for X.
We have: log2a(4a2e7)=log4x(x+1)1.
Rewriting with change of base: ln(2a)ln(4a2e7)=−log4(x(x+1)).
Substitute known values and solve: 4a2e7=1/(x2+x).
Framing: Solve x2+x−(4a2e7)=0.
The solution for X is found by applying the quadratic formula:
Therefore, the solution to the problem is X=−21+21+4−13.