已知:A=1+2a^2b-3a^3,B=2a^3-2ab^2-2,求2A-3B的值
问题描述:
已知:A=1+2a^2b-3a^3,B=2a^3-2ab^2-2,求2A-3B的值
答
2A-3B
=2(1+2a^2b-3a^3)-3(2a^3-2ab^2-2)
=2+4a^2b-6a^3-6a^3+6ab^2+6
=4a^2b-12a^3+6ab^2+8