求A,B,C的值
2
1. Cx +A(x+1)-B=2(x+3)+3(x-2)
↑
係Cx 2次
教我點做thx~
F.2 數學 急急急~~~(恆等式)
2010-10-08 10:36 pm
回答 (2)
2010-10-08 11:01 pm
✔ 最佳答案
Cx^2 +A(x+1)-B=2(x+3)+3(x-2)L.H.S=Cx^2+A(x+1)-B
=Cx^2+Ax+A-B
=Cx^2+Ax+(A-B)
R.H.S=2(x+3)+3(x-2)
=2x+6+3x-6
=5x
By comparing the likes term on L.H.S and R.H.S
Cx^2=0
C=0
Ax=5x
A=5
(A-B)=0
5-B=0
B=5
2010-10-08 15:02:10 補充：
since R.H.S=0x^2+5x+0
參考: me
2010-10-10 8:49 am
1) Cx^2+A(x+1)-B=2(x+3)+3(x-2)
左方=Cx^2+A(x+1)-B
=Cx^2+Ax+A-B
=Cx^2+Ax+(A-B)
右方=2(x+3)+3(x-2)
=2x+6+3x-6
=5x
C=0
(因為右方冇x^2)
Ax=5x
A=5
(A-B)
A-B=5-B=0
B=5
左方=Cx^2+A(x+1)-B
=Cx^2+Ax+A-B
=Cx^2+Ax+(A-B)
右方=2(x+3)+3(x-2)
=2x+6+3x-6
=5x
C=0
(因為右方冇x^2)
Ax=5x
A=5
(A-B)
A-B=5-B=0
B=5
參考: 自己
收錄日期: 2021-04-19 23:26:17
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20101008000051KK00549