12) -0,36p2q+0,73q2p+ 27 pq2-0,64p2q = 100

12) Приведем подобные члены: $$-0.36p^2q + 0.73q^2p + \frac{27}{100}pq^2 - 0.64p^2q = (-0.36p^2q - 0.64p^2q) + (0.73q^2p + \frac{27}{100}pq^2) = -1p^2q + (0.73q^2p + 0.27pq^2) = -p^2q + q^2p$$

Ответ: $$-p^2q + q^2p$$