Starnge Operators

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carllecat
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Topic: Starnge Operators
PostTue Nov 17, 2009 9:16 am
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If the operation Θ is defined for all integers A and B by A Θ B = A + B - AB, which of the following statements must be true for all integers A, B and C?

I. A Θ B = B Θ A
II. A Θ 0 = A
III. (A Θ B) Θ C = A Θ (B Θ C)

A) I only
B) II only
C) I and II only
D) I and III only
E) I, II and III

Answer to be posted later.
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carllecat
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PostTue Nov 17, 2009 9:41 am
E) I, II and III
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carllecat
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PostThu Nov 19, 2009 8:19 am
Anyone???
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satish.nagdev
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PostThu Nov 19, 2009 11:58 pm
you just have to verify each of 3 against given info

A Θ B = A + B - AB

1) B Θ A = B + A - BA which is = A Θ B, so its true

2) A Θ 0 = A + 0 - 0 = A, hence true

3) I am leaving it to you it's pretty simple I guess.
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PostFri Nov 20, 2009 1:57 am
yeah its E

1) A+B-AB=B+A-BA
2)A+0-A*0=A
3)A+B+C_AB-AC-BC+ABC=A+B+C-AB-AC-BC+ABC
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