去括号(1)()abc温故而知新(2)()aabaca(4)()aa(3)()aa(5)()aa=(-1)x(3-7)复习旧知-(+5)=+(+5)=-(-7)=+(-7)=-5+5+7-71.化简=(-1)x3+(-1)x(-7)=-3+7=1x3+1x(-7)=3-72.去括号①-(3-7)②+(3-7)...
时间:2024-11-13 16:51栏目:演讲稿