(3a^2-ab+7)-(-4a^2+2ab+7)=
问题描述:
(3a^2-ab+7)-(-4a^2+2ab+7)=
答
(3a^2-ab+7)-(-4a^2+2ab+7)
=3a^2+4a^2-ab-2ab+7-7
=7a^2-3ab你确定对确定