a 9 z + a 8 z 2 + a 7 z 3 − a 7 z + a 6 z 4 − 3 a 6 z 2 + 2 a 6 + a 5 z 3 − 2 a 5 z + a 4 z 4 − 4 a 4 z 2 + 3 a 4 {\displaystyle a^{9}z+a^{8}z^{2}+a^{7}z^{3}-a^{7}z+a^{6}z^{4}-3a^{6}z^{2}+2a^{6}+a^{5}z^{3}-2a^{5}z+a^{4}z^{4}-4a^{4}z^{2}+3a^{4}}
