− 2 v 2 u 4 + 2 v u 4 + 7 v 2 u 3 − 9 v u 3 + 3 u 3 − 8 v 2 u 2 + 15 v u 2 − 8 u 2 + 3 v 2 u − 9 v u + 7 u + 2 v − 2 {\displaystyle -2v^{2}u^{4}+2vu^{4}+7v^{2}u^{3}-9vu^{3}+3u^{3}-8v^{2}u^{2}+15vu^{2}-8u^{2}+3v^{2}u-9vu+7u+2v-2}
