-3(a^2bc)^2*1/2a(bc)^3-（abc）^3*(-abc)^2
=-3a^4b^2c^2*1/2ab^3c^3-（abc）^3*(abc)^2
=-3/2*a^5b^5c^5-(abc)^5
=-3/2*(abc)^5-(abc)^5
=-5/2(abc)^5