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by amitdgr » Fri Jul 11, 2008 1:05 am
If r☉s = rs + r + s, then for what value of s is r ☉s equal to r for all values of r?
The question asks -> For what value of s, rs + r + s will be = r

we can clearly see, When s=0 => rs + r + s =r

Otherwise, plug in the answer choices in the above equation and see for which choice we satisfy the equation rs + r + s=r

Is the OA B) 0 ?

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Re: NO idea where to begin...

by parallel_chase » Fri Jul 11, 2008 6:10 am
smclean23 wrote:If r☉s = rs + r + s, then for what value of s is r ☉s equal to r for all values of r?
(A) –1 (B) 0 (C) 1
(D) (E) r

r☉s = rs + r + s =>

r☉s = s(r+1) + r

Therefore only value of S for r☉s = r is 0.

Hence answer B.

What is OA?
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