合并同类项,去括号 7a+3(a+3b)7a+3(a+3b)3x-(4y-2y+1)
问题描述:
合并同类项,去括号 7a+3(a+3b)
7a+3(a+3b)
3x-(4y-2y+1)
答
7a+3(a+3b)=7a+3a+9b=10a+9b
3x-(4y-2y+1)=3x-(2y+1)=3x-2y-1
答
7a+3(a+3b)
=7a+3a+9b
=10a+9b
3x-(4y-2y+1)
=3x-4y+2y-1
=3x-2y-1