GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 15 Aug 2018, 13:55

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

If a(x) = 2x^2 + 2, which of the following is equal to a(4)?

Author Message
TAGS:

Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 47920
If a(x) = 2x^2 + 2, which of the following is equal to a(4)?  [#permalink]

Show Tags

27 Jul 2018, 01:30
00:00

Difficulty:

15% (low)

Question Stats:

83% (00:58) correct 17% (01:20) wrong based on 30 sessions

HideShow timer Statistics

If $$\alpha(x)= 2x^2 + 2$$, which of the following is equal to $$\alpha(4)$$ ?

(A) $$\alpha(\alpha(-1))$$

(B) $$\alpha(-2)$$

(C) $$\alpha(\alpha(2))$$

(D) $$\alpha(17)$$

(E) $$\alpha(34)$$

_________________
RC Moderator
Status: Perfecting myself for GMAT
Joined: 22 May 2017
Posts: 418
Concentration: Nonprofit
Schools: Haas '21
GPA: 4
WE: Engineering (Computer Software)
Re: If a(x) = 2x^2 + 2, which of the following is equal to a(4)?  [#permalink]

Show Tags

27 Jul 2018, 01:49
2
a(x) = $$2x^2 + 2$$

a(x) = $$2(4)^2 + 2$$ = 2(16) + 2 = 34

option A

a(a(-1))

a(-1) = $$2(-1)^2 + 2$$ = 2 + 2 = 4

=> a(a(-1)) = a(4)

Hence option A
_________________

If you like my post press kudos +1

New - RC Butler - 2 RC's everyday

Tag me in RC questions if you need help. Please provide your analysis of the question in the post along with the tag.

Director
Joined: 30 Jan 2015
Posts: 520
Location: India
Concentration: Operations, Marketing
GPA: 3.5
Re: If a(x) = 2x^2 + 2, which of the following is equal to a(4)?  [#permalink]

Show Tags

27 Jul 2018, 02:21
Starting off with Option A)
= α( α(-1) )
= α( 2*(-1)^2 + 2 )
= α( 2 + 2 )
= α(4)

Hence, A.
_________________

The few, the fearless !

Thanks

Senior Manager
Joined: 21 Jan 2015
Posts: 343
Location: India
Concentration: Strategy, Marketing
GMAT 1: 620 Q48 V28
WE: Sales (Consumer Products)
Re: If a(x) = 2x^2 + 2, which of the following is equal to a(4)?  [#permalink]

Show Tags

27 Jul 2018, 03:05
Ans: A

Question is asking which of these is equal to $$\alpha(4)$$
for not invoilinvg formating i am writting Alpha as F so
give a(x) = 2(x^2 + 1)
we need to find equivalent of a(4); so in other words we don't need to find the value of a(4) just find if the values in the a() is equivalent to 4 or not.. and also check of negatives only because there is no division or substation in the function so value will always increase as the input increases.

Ans: A
Bunuel wrote:
If $$\alpha(x)= 2x^2 + 2$$, which of the following is equal to $$\alpha(4)$$ ?

_________________

--------------------------------------------------------------------
The Mind is Everything, What we Think we Become.
Kudos will encourage many others, like me.
Thanks

Re: If a(x) = 2x^2 + 2, which of the following is equal to a(4)? &nbs [#permalink] 27 Jul 2018, 03:05
Display posts from previous: Sort by

Events & Promotions

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.