Add $ \dfrac{1}{x} $ and $ 1 $ to get $ \dfrac{ \color{purple}{ x+1 } }{ x }$.

Step 1: Write $ 1 $ 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 second fraction by $\color{blue}{x}$.

$$ \begin{aligned} \frac{1}{x} +1 & \xlongequal{\text{Step 1}} \frac{1}{x} + \frac{1}{\color{red}{1}} = \frac{ 1 }{ x } + \frac{ 1 \cdot \color{blue}{ x }}{ 1 \cdot \color{blue}{ x }} = \\[1ex] & \xlongequal{\text{Step 2}} \frac{ \color{purple}{ 1 } }{ x } + \frac{ \color{purple}{ x } }{ x }=\frac{ \color{purple}{ x+1 } }{ x } \end{aligned} $$

Subtract $ \dfrac{4}{x} $ from $ \dfrac{x+1}{x} $ to get $ \dfrac{x-3}{x} $.

To subtract expressions with the same denominators, we subtract the numerators and write the result over the common denominator.

$$ \begin{aligned} \frac{x+1}{x} - \frac{4}{x} & = \frac{x+1}{\color{blue}{x}} - \frac{4}{\color{blue}{x}} =\frac{ x+1 - 4 }{ \color{blue}{ x }} = \\[1ex] &= \frac{x-3}{x} \end{aligned} $$

Add $ \dfrac{x-3}{x} $ and $ 3 $ to get $ \dfrac{ \color{purple}{ 4x-3 } }{ x }$.

Step 1: Write $ 3 $ 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 second fraction by $\color{blue}{x}$.

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