(A+B)+(A-B)x=3x+5

(A+B)+(A-B)x=3x+5
A+B+(A-B)x=3x+5
(A – B)x – 3x = 5 – A – B
(A – B – 3)x = 5 – A – B
x = (5 – A – B) / (A – B – 3)

2006-11-07 19:20:50 補充：
若這題不是方程式，而是恒等式則(A+B)+(A-B)x=3x+5A + B = 5 ___(1)A – B = 3 ___(2)(1)式加(2)式2A = 8A = 4(1)式減(2)式2B = 2B = 1

唔知你想求邊個unknown
求x的話：
(A+B)+(A-B)x=3x+5
A+B=3x+5-(A-B)x
A+B=x(3-A+B)+5
A+B-5=x(3-A+B)
x=A+B-5
ˉ----------
ˉ3-A+B

(A+B)+(A-B)X+3X+5=A+B+A-B*X=3X+5
A*X=3X+5....................................
SOR真係唔識最多係咁多

comparing the coefficient
A+B=3
A-B=5

2A=8
A=4
B=-1

(A+B)+(A-B)x=3x+5

A+B+(A-B)x=3x+5

(A – B)x – 3x = 5 – A – B

(A – B – 3)x = 5 – A – B

x = (5 – A – B) / (A – B – 3)

我不明白
sorry.........

我不明白你想發問什麼 ?
sorry !

comparing the coefficient
A+B=3
A-B=5

2A=8
A=4
B=-1

2007-04-17 17:47:16 補充：
x = (5 – A – B) / (A – B – 3)