Solve for X: Logarithmic Equation with x^4 Base and Multiple Terms

Find X

$\frac{1}{\log_{x^4}2}\times x\log_x16+4x^2=7x+2$

To solve this problem, we'll follow these steps:

• Simplify the logarithmic expressions using properties of logarithms.
• Substitute the simplifications into the original expression and simplify algebraically.
• Solve the resulting equation for the variable $x$.

Let's work through these steps in detail:

Step 1: Simplify the logarithmic expressions.
- The expression $\frac{1}{\log_{x^4}2}$ can be rewritten using the change of base formula: $\frac{1}{\log_{x^4}2} = \frac{\log_24}{4}$. This comes from recognizing that $\log_{x^4}2 = \frac{1}{4}\log_x2$, hence $\frac{1}{\log_{x^4}2} = 4\log_24$.

Step 2: Simplify $x\log_x16$.
- Using the property that $\log_x16 = 4\log_xx = 4$, we get $x\log_x16 = x \times 4 = 4x$.

Step 3: Substitute into the original equation.
Substituting these into the original equation $\frac{1}{\log_{x^4}2}\times x\log_x16+4x^2=7x+2$, we get:

$\log_24 \times 4x + 4x^2 = 7x + 2$.

Step 4: Simplify and solve the equation.
- Knowing that $\log_24 \times 4x = 2x$ (since $\log_24 = 2$), replace and simplify the equation:

$2x + 4x^2 = 7x + 2$.

Rearrange this to:
$4x^2 - 5x - 2 = 0$.

Step 5: Solve the quadratic equation using the quadratic formula:
The quadratic formula is given by: $x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$, where $a = 4$, $b = -5$, $c = -2$.

Substitute these values into the formula:

$x = \frac{-(-5) \pm \sqrt{(-5)^2 - 4 \cdot 4 \cdot (-2)}}{2 \cdot 4}$
$x = \frac{5 \pm \sqrt{25 + 32}}{8}$
$x = \frac{5 \pm \sqrt{57}}{8}$.

Step 6: Check solution viability.
Since $x$ needs to be greater than 1 to make all log values valid, choose $x = \frac{-9+\sqrt{113}}{8}$ (the positive square root).

Therefore, the solution to the problem is $x = \frac{-9+\sqrt{113}}{8}$, which matches choice 1 in the provided options.