F.2數學題(Ax+2-B(x-3)≡3x+14求常數A和B的值)

2008-06-08 7:35 pm
Ax+2-B(x-3)≡3x+14求常數A和B的值
更新1:

(Ax+B)(3x-4)≡6x²-23x+20求常數A和B的值

回答 (3)

2008-06-08 7:57 pm
✔ 最佳答案
左方=Ax+2-B(x-3)
=Ax-Bx+2+3B
=(A-B)x+2+3B
比較左方和右方同類項,可得
A-B=3_____________(1)
2+3B=14___________(2)
從(2)得,
B=4
把B=4代入(1),可得
A-(4)=5
A=9
∴A=9,B=4 //


2008-06-08 12:05:01 補充:
把B=4代入(1),可得

A-(4)=3

A=7

∴A=7,B=4 //
2008-06-08 7:42 pm
Ax+2-B(x-3)≡3x+14

Ax-Bx+3B≡3x+12

(A-B)x+3B≡3x+12

B = 12/3 = 4

A = 3+4 = 7

2008-06-08 12:28:12 補充:
3B≡12

(A-B)x≡3x
參考: 自己
2008-06-08 7:42 pm
2 + 3B = 14
3B = 12
B = 4

A - B = 3
Because B = 4
A - 4 = 3
A = 7

You have to expand the left hand side and group the like terms and compare
them with the right hand side, NEVER transpose terms in both sides.
Remember, this is an idnetity, not an equation.
參考: myself


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