find the values of A and B for the following identity in x:
(A-B)x + (A+B) ≡ 7x + 3
MTH( F.2數學題)
2007-07-07 6:22 pm
回答 (5)
2007-07-07 9:44 pm
✔ 最佳答案
(A - B)x + (A + B) ≡ 7x + 3Since this is an identity. So, this equation is always true for all values of x
Comparing the coefficient,
A - B = 7 ─── (1)
A + B = 3 ─── (2)
(1) - (2):
(A - B) - (A + B) = 7 - 3
-2B = 4
B = 4/(-2)
B = -2
So, sub B = -2 into (1):
A - (-2) = 7
A + 2 = 7
A = 5
參考: Myself~~~
2007-07-08 6:38 am
(A-B)x + (A+B) ≡ 7x + 3
A = 5 / b = -2
A = 5 / b = -2
2007-07-08 12:37 am
find the values of A and B for the following identity in x:
(A-B)x + (A+B) ≡ 7x + 3
(A-B)x + (A+B) ≡ 7x + 3
Ax-Bx+A+B=7X+3
Ax-Bx=7x
A-B=7
A=7+B--(1)
A+B=3--(2)
put (1) into (2)
7+B+B=3
2B=3-7
B=-2
put B=-2 into (1)
A=7+(-2)
A=5
so A=5,B=-2
(A-B)x + (A+B) ≡ 7x + 3
(A-B)x + (A+B) ≡ 7x + 3
Ax-Bx+A+B=7X+3
Ax-Bx=7x
A-B=7
A=7+B--(1)
A+B=3--(2)
put (1) into (2)
7+B+B=3
2B=3-7
B=-2
put B=-2 into (1)
A=7+(-2)
A=5
so A=5,B=-2
2007-07-07 10:51 pm
(A-B)x + (A+B) ≡ 7x + 3
Ax-Bx+A+B=7X+3
Ax-Bx=7x
A-B=7
A=7+B--(1)
A+B=3--(2)
put (1) into (2)
7+B+B=3
2B=3-7
B=-2
put B=-2 into (1)
A=7+(-2)
A=5
so A=5,B=-2
Ax-Bx+A+B=7X+3
Ax-Bx=7x
A-B=7
A=7+B--(1)
A+B=3--(2)
put (1) into (2)
7+B+B=3
2B=3-7
B=-2
put B=-2 into (1)
A=7+(-2)
A=5
so A=5,B=-2
參考: 自己
2007-07-07 6:37 pm
(A-B)x + (A+B) ≡ 7x + 3
A-B=7 &
A+B=3
A = 5 and b = -2
A-B=7 &
A+B=3
A = 5 and b = -2
收錄日期: 2021-04-13 17:37:41
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20070707000051KK00881