已知A=—3ax ^2-AX+3,B=—ax-1/2ax-1

问题描述:

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