已知A=—3ax ^2-AX+3,B=—ax-1/2ax-1(1)求1/3A-B?(2)当a=2,x=3时求(1)的结果

来源:学生作业学帮网 编辑:学帮网 时间:2024/05/27 18:02:22

已知A=—3ax ^2-AX+3,B=—ax-1/2ax-1
(1)求1/3A-B?
(2)当a=2,x=3时求(1)的结果

1/3A-B
=1/3*(-3ax^2-ax+3)-(-ax^2-1/2ax-1)
=-ax^2-1/3ax+1+ax^2+1/2ax+1
=1/6ax+2
当a=2,x=3时
1/6ax+2
=1/6*2*3+2
=1+2
=3

1/3A-B
=1/3*(-3ax^2-ax+3)-(-ax^2-1/2ax-1)
=-ax^2-1/3ax+1+ax^2+1/2ax+1
=1/6ax+2
当a=2,x=3时
1/6ax+2
=1/6*2*3+2
=1+2
=3