$$x = \frac { 3 } { 4 } , y = \frac { 4 } { 5 } z = \frac { 2 } { 3 } \quad x = \frac { - 1 } { 3 }$$
$x=\frac{3}{4}=0.75$
$y=\frac{4z}{5}$
$z\in \mathrm{C}$
$x=\frac{3}{4}=0.75$
$y=\frac{4z}{5}$
$z\in \mathrm{R}$
