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# What is the value of x^2 - 2x - 14?

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Intern
Joined: 24 Aug 2017
Posts: 8
What is the value of x^2 - 2x - 14?  [#permalink]

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11 Oct 2017, 21:53
5
00:00

Difficulty:

55% (hard)

Question Stats:

52% (01:21) correct 48% (01:27) wrong based on 103 sessions

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What is the value of $$x^2 - 2x - 14$$?

1) x < 0
2) (x-5)(x+3) = 0
Manager
Joined: 05 Dec 2016
Posts: 246
Concentration: Strategy, Finance
GMAT 1: 620 Q46 V29
Re: What is the value of x^2 - 2x - 14?  [#permalink]

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11 Oct 2017, 23:24
1
(1) Insufficient
(2) both roots of x=-3;5 give the same value when substituted to equation in stimulus

Intern
Joined: 29 Aug 2017
Posts: 1
Re: What is the value of x^2 - 2x - 14?  [#permalink]

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22 Oct 2017, 12:41
Why is the answer not D?

x^2 -2x - 14 has solutions x = 1 + sqrt(15) and 1 - sqrt(15) using the quadratic formula. Only one of the two solutions is negative, so isn't A sufficient as well?
Intern
Joined: 05 Oct 2017
Posts: 13
GMAT 1: 650 Q48 V32
WE: Consulting (Consulting)
Re: What is the value of x^2 - 2x - 14?  [#permalink]

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22 Oct 2017, 12:54
wewewe2 wrote:
Why is the answer not D?

x^2 -2x - 14 has solutions x = 1 + sqrt(15) and 1 - sqrt(15) using the quadratic formula. Only one of the two solutions is negative, so isn't A sufficient as well?

I was thinking the same way, please explain in detail anyone
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What is the value of x^2 - 2x - 14?  [#permalink]

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22 Oct 2017, 13:12
2
jajanb wrote:
wewewe2 wrote:
Why is the answer not D?

x^2 -2x - 14 has solutions x = 1 + sqrt(15) and 1 - sqrt(15) using the quadratic formula. Only one of the two solutions is negative, so isn't A sufficient as well?

I was thinking the same way, please explain in detail anyone

Hi wewewe2 & jajanb

The question asks to find the value of the equation $$f(x)=x^2-2x-14$$. we are not asked to calculate the roots of $$f(x)$$

it is not given that $$f(x)=0$$ here, hence you cannot calculate the roots of the equation.

From statement 1 you get multiple values of $$x$$, hence there will be multiple values of $$f(x)$$. Insufficient

Statement 2: implies that $$x=-3$$ or $$5$$. in either case $$f(x)$$ yields the same result i.e $$f(-3)=f(5)=1$$. Hence sufficient

Option B
What is the value of x^2 - 2x - 14? &nbs [#permalink] 22 Oct 2017, 13:12
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