^是次方的意思
(2分之1ab的2次方-3分之1a的2次方b-6ab)×(-6ab)
=(1/2 ab^2-1/3 a^2b- 6ab)×(-6ab)
=(-1/2×6)a^(1+1)b^(2+1)+(1/3×6)a^(2+1)b^(1+1)+(6×6)a^(1+1)b^(1+1)
=-3a^2b^3+2a^3b^2+36a^2b^2