− v 3 u 3 + 2 v 2 u 3 − v u 2 + 2 u 2 + 2 v 3 u − v 2 u + 2 v − 1 {\displaystyle -v^{3}u^{3}+2v^{2}u^{3}-vu^{2}+2u^{2}+2v^{3}u-v^{2}u+2v-1}
