− 5 v u 3 + 5 u 3 + 13 v u 2 − 13 u 2 − 13 v u + 13 u + 5 v − 5 {\displaystyle -5vu^{3}+5u^{3}+13vu^{2}-13u^{2}-13vu+13u+5v-5}
