$$81 { A }^{ 4 } { B }^{ 8 } -29Z { A }^{ 2 } { B }^{ 4 } { x }^{ 8 } +256 { x }^{ 16 }$$
$256x^{16}-29ZA^{2}B^{4}x^{8}+81A^{4}B^{8}$
$4096x^{15}-232ZA^{2}B^{4}x^{7}$
