− 2 v u 3 + 2 u 3 + 8 v u 2 − 8 u 2 − 8 v u + 8 u + 2 v − 2 {\displaystyle -2vu^{3}+2u^{3}+8vu^{2}-8u^{2}-8vu+8u+2v-2}
