value of n

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value of n

by ManSab » Thu Jul 09, 2009 1:29 pm
f(x) = x2 + 4x + k = 12; f(-6) = 0; if k is a constant and n is the number for which f(n) = 0, what is the value of n?
A) 6
B) 2
C) 0
D) -2
E) -12

OA - B

Please explain your answers..

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Answer is A) 6

by srk1708 » Thu Jul 09, 2009 1:41 pm
The value of K can be determined as -48 by using the function f(-6)=0. Substituting the value of K, the function becomes x2+4x-48=12.

So substituting the first option A)6, the equation is satisifed....

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by shibal » Thu Jul 09, 2009 2:00 pm
actually x^2+4x-12=0 is (x+6)(x-2) therefore solutions are -6 and 2, hence answer should be b

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by talk_to_me_cal » Fri Jul 10, 2009 5:12 pm
I think the correct answer is B. Thanks shibal