Multiply $ \dfrac{1}{9} $ by $ x^4 $ to get $ \dfrac{ x^4 }{ 9 } $.

Step 1: Write $ x^4 $ as a fraction by putting $ \color{red}{ 1 } $ in the denominator.

Step 2: Multiply numerators and denominators.

Step 3: Simplify numerator and denominator.

$$ \begin{aligned} \frac{1}{9} \cdot x^4 & \xlongequal{\text{Step 1}} \frac{1}{9} \cdot \frac{x^4}{\color{red}{1}} \xlongequal{\text{Step 2}} \frac{ 1 \cdot x^4 }{ 9 \cdot 1 } = \\[1ex] & \xlongequal{\text{Step 3}} \frac{ x^4 }{ 9 } \end{aligned} $$

Add $36+4x^2$ and $ \dfrac{x^4}{9} $ to get $ \dfrac{ \color{purple}{ x^4+36x^2+324 } }{ 9 }$.

Step 1: Write $ 36+4x^2 $ as a fraction by putting $ \color{red}{ 1 } $ in the denominator.

Step 2: To add raitonal expressions, both fractions must have the same denominator.
We can create a common denominator by multiplying the first fraction by $\color{blue}{ 9 }$.

$$ \begin{aligned} 36+4x^2+ \frac{x^4}{9} & \xlongequal{\text{Step 1}} \frac{36+4x^2}{\color{red}{1}} + \frac{x^4}{9} = \frac{ \left( 36+4x^2 \right) \cdot \color{blue}{ 9 }}{ 1 \cdot \color{blue}{ 9 }} + \frac{ x^4 }{ 9 } = \\[1ex] & \xlongequal{\text{Step 2}} \frac{ \color{purple}{ 324+36x^2 } }{ 9 } + \frac{ \color{purple}{ x^4 } }{ 9 }=\frac{ \color{purple}{ x^4+36x^2+324 } }{ 9 } \end{aligned} $$

Multiply $qrst$ by $ \dfrac{x^4+36x^2+324}{9} $ to get $ \dfrac{ qrstx^4+36qrstx^2+324qrst }{ 9 } $.

Step 1: Write $ qrst $ as a fraction by putting $ \color{red}{1} $ in the denominator.

Step 2: Multiply numerators and denominators.

Step 3: Simplify numerator and denominator.

$$ \begin{aligned} qrst \cdot \frac{x^4+36x^2+324}{9} & \xlongequal{\text{Step 1}} \frac{qrst}{\color{red}{1}} \cdot \frac{x^4+36x^2+324}{9} \xlongequal{\text{Step 2}} \frac{ qrst \cdot \left( x^4+36x^2+324 \right) }{ 1 \cdot 9 } = \\[1ex] & \xlongequal{\text{Step 3}} \frac{ qrstx^4+36qrstx^2+324qrst }{ 9 } \end{aligned} $$