来自孙永香的问题
【先去括号,在合并同类项①-(x+y)+(3x-7y)②2a+2(a+1)-3(a-1)③4a^2-3a+3-3(-a^3+2a^2+1)】
先去括号,在合并同类项①-(x+y)+(3x-7y)②2a+2(a+1)-3(a-1)③4a^2-3a+3-3(-a^3+2a^2+1)
1回答
2019-12-28 01:06
【先去括号,在合并同类项①-(x+y)+(3x-7y)②2a+2(a+1)-3(a-1)③4a^2-3a+3-3(-a^3+2a^2+1)】
先去括号,在合并同类项①-(x+y)+(3x-7y)②2a+2(a+1)-3(a-1)③4a^2-3a+3-3(-a^3+2a^2+1)
①-(x+y)+(3x-7y)
=-x-y+3x-7y=2x-8y
②2a+2(a+1)-3(a-1)
=2a+2a+2-3a+3=a+5
③4a^2-3a+3-3(-a^3+2a^2+1)
=4a^2-3a+3+3a^3-6a^2-3
=3a^3-2a^2-3a
=a(3a^2-2a-3)