$\left\{\begin{array} { l } x=\frac{ 3 }{ 4 }+\frac{ 1 }{ 3 }y \\ 9x-3y=\frac{ 27 }{ 4 }\end{array} \right.$
Substitute the given value of $x$ into the equation $9x-3y=\frac{ 27 }{ 4 }$$9\left( \frac{ 3 }{ 4 }+\frac{ 1 }{ 3 }y \right)-3y=\frac{ 27 }{ 4 }$
Solve the equation for $y$$y \in ℝ$
The statement is true for any value of $y$ and $x$ that satisfy both equations from the system. Therefore, the solution in parametric form is$\begin{array} { l }\left( x, y\right)=\left( \frac{ 3 }{ 4 }+\frac{ 1 }{ 3 }y, y\right),& y \in ℝ\end{array}$