Add $ \dfrac{x}{2} $ and $ \dfrac{6}{y} $ to get $ \dfrac{ \color{purple}{ xy+12 } }{ 2y }$.

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}{ y }$ and the second by $\color{blue}{ 2 }$.

$$ \begin{aligned} \frac{x}{2} + \frac{6}{y} & = \frac{ x \cdot \color{blue}{ y }}{ 2 \cdot \color{blue}{ y }} + \frac{ 6 \cdot \color{blue}{ 2 }}{ y \cdot \color{blue}{ 2 }} = \\[1ex] &=\frac{ \color{purple}{ xy } }{ 2y } + \frac{ \color{purple}{ 12 } }{ 2y }=\frac{ \color{purple}{ xy+12 } }{ 2y } \end{aligned} $$