logx31×x2logx127+4x+6=0
x=?
To solve the given equation, we need to simplify the logarithmic expressions and then solve for x. Let's proceed with the given equation:
logx31×x2log1/x27+4x+6=0
Step 1: Simplify the logarithmic terms.
Apply the change of base formula to the logarithms:
logx3=lnxln3
Thus, logx31=ln3lnx.
For the second logarithmic term: log1/x27=−logx27=−lnxln27.
Step 2: Substitute these simplifications back into the equation.
We have:
ln3lnx×x2×−lnxln27+4x+6=0
Simplify this expression:
The lnx terms cancel each other out in the expression ln3lnx×x2×−lnxln27.
Thus, it becomes:
−ln3ln27x2+4x+6=0
The value of −ln3ln27 is actually −log327=−3 because 27=33.
Therefore, the simplified equation is:
−3x2+4x+6=0
Step 3: Solve the quadratic equation.
Rearrange it to 3x2−4x−6=0.
Apply the quadratic formula: x=2a−b±b2−4ac.
Here, a=3, b=−4, c=−6.
So, the solution becomes:
x=2×34±(−4)2−4×3×(−6)
This simplifies to:
x=64±16+72
x=64±88
Simplify 88=4×22=222.
Thus,
x=64±222
Simplifying further gives us:
x=32±22
The valid positive solution (since logarithms are not satisfied with negative bases) is:
x=32+322
Therefore, the correct answer is choice 3: 32+322.
32+322