a 6 ( − z 2 ) − 2 a 6 + a 4 z 4 + 4 a 4 z 2 + 3 a 4 {\displaystyle a^{6}\left(-z^{2}\right)-2a^{6}+a^{4}z^{4}+4a^{4}z^{2}+3a^{4}}
