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

發問:

(A+B)+(A-B)x=3x+5 這是一條恆等式，我想知步驟。Thank you.

最佳解答:

(A+B)+(A-B)x=3x+5 A + B = 5 ___(1) A – B = 3 ___(2) (1)式加(2)式 2A = 8 A = 4 (1)式減(2)式 2B = 2 B = 1

其他解答:

(A + B) = 5 and (A - B) = 3 i.e. A - B = 3 A = 3 + B substitute into A + B = 5 3 + B + B = 5 2B = 2 B = 1 then substitute B = 1 into A = 3 + B = 3 + 1 = 4 thus, A = 4 and B =1|||||A-B=3 A+B=5 A=4 B=1|||||let a + b = 5 ( 1 ) let a - b = 3 ( 2 ) ( 1 ) + ( 2 ) 2a = 8 a = 4# Sub a = 4 to ( 2 ) 4 - b = 3 b = 1#|||||(A+B)+(A-B)x=3x+5 Therefore, A+B=5 and A-B=3 Therefore, A =4, B =1