$${ \left( \frac{ 7x }{ 9 } + \frac{ 9y }{ 8 } + \frac{ 8z }{ 7 } \right) }^{ 2 }$$
$\frac{\left(392x+567y+576z\right)^{2}}{254016}$
$\frac{7xy}{4}+\frac{16xz}{9}+\frac{18yz}{7}+\frac{49x^{2}}{81}+\frac{64z^{2}}{49}+\frac{81y^{2}}{64}$
