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Real numbers

by greenwich » Sat May 04, 2013 1:01 pm
For which real numbers x is the expression 2/((x-2)(x+1)) not defined?

(A) x=0 only
(B) x=2 only
(C) x=-1 only
(D) x=-1 or 2
(E)x=-1, 0 or 2
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by srcc25anu » Sat May 04, 2013 1:06 pm
Any value for x that makes the denominator 0 will make the expression 2/((x-2)(x+1)) UNDEFINED
So if x = 2, the term (x-2) will become 0 or if x = -1, then term (x+1) will become zero. In either case, the denominator will reduce to 0

Ans D
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by greenwich » Sat May 04, 2013 4:10 pm
why not b or c?
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by killerdrummer » Sun May 05, 2013 7:10 am
Because answer choices B & C say 2 only and -1 only respectively ..Clearly there are two unique values !
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