Last visit was: 25 Dec 2024, 09:29 It is currently 25 Dec 2024, 09:29
Decision Tracker
My Rewards
New comers' posts
New posts
Unanswered

Close

GRE Prep 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
Your Progress

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

Practice
Pays

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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Go to My Error Log Learn more
Close

Request Expert Reply

Confirm Cancel
PREVIOUS TOPIC
NEXT TOPIC

f(x)=3x^2−15x+16

Tags :
Find Similar Topics  About  Add a Tag

Show Tags
Hide Tags

avatar
S
Asmakan
Senior Manager
Senior Manager
Joined: 17 Aug 2019
Posts: 381
Own Kudos [?]: 203 [2]
Given Kudos: 96
Send PM
f(x)=3x^2−15x+16 [#permalink] New post   Updated on: 16 Sep 2019, 01:05
1
1
Bookmarks
00:00

Question Stats:

52% (01:50) correct 48% (01:58) wrong based on 25 sessions

Hide Show timer Statistics

\(f(x)=3x^2−15x+16\) and \(g(x)=x^2−5x+5\)

Quantity A
Quantity B
The sum of the roots of \(f(x)\)
The sum of the roots of \(g(x)\)



A)The quantity in Column A is greater.
B)The quantity in Column B is greater.
C)The two quantities are equal.
D)The relationship cannot be determined from the information given.
ShowHide Answer
Official Answer
C

Originally posted by Asmakan on 15 Sep 2019, 00:44.
Last edited by pranab223 on 16 Sep 2019, 01:05, edited 3 times in total.
Edited by Carcass
avatar
Kunal14
Intern
Intern
Joined: 29 Jul 2019
Posts: 1
Own Kudos [?]: 2 [0]
Given Kudos: 0
Send PM
Re: f(x)=3x^2−15x+16 [#permalink] New post   15 Sep 2019, 23:28
2
Sum of roots of any quadratic equation is always equal to -b\a and the product of roots is c\a.

Therefore,

For Quantity A
-(-15\3) = 5

For Quantity B
-(-5\1) = 5

Hence C.
avatar
pranab223
Retired Moderator
Joined: 20 Apr 2016
Posts: 1307
Own Kudos [?]: 2281 [2]
Given Kudos: 251
WE:Engineering (Energy and Utilities)
Send PM

Top Member of the Month
Re: f(x)=3x^2−15x+16 [#permalink] New post   16 Sep 2019, 01:03
2
Asmakan wrote:
\(f(x)=3x^2−15x+16\) and \(g(x)=x^2−5x+5\)

Quantity A
Quantity B
The sum of the roots of \(f(x)\)
The sum of the roots of \(g(x)\)



A)The quantity in Column A is greater.
B)The quantity in Column B is greater.
C)The two quantities are equal.
D)The relationship cannot be determined from the information given.


May someone explains why the answer is C ?

Note: I tried to figure out how to post a and b exact form but couldn't find.


In a quadratic Equation: \(ax^2 + bx + c\)

The sum of the roots is = \(\frac{-b}{a}\)

and the product of the roots is = \(\frac{c}{a}\)


In the above equation :: \(f(x)=3x^2−15x+16\)

b = -15

and a = 3

The sum of the roots = \(\frac{-(-15)}{3} = 5\)

For the next equation ::\(g(x)=x^2−5x+5\)

b = -5

and a =1

The sum of the roots = \(\frac{-(-5)}{1} = 5\)


Here is the link :: https://www.mathwarehouse.com/quadratic/roots/formula-sum-product-of-roots.php
avatar
greMS15
Manager
Manager
Joined: 21 Oct 2015
Posts: 64
Own Kudos [?]: 48 [0]
Given Kudos: 0
Send PM
Re: f(x)=3x^2−15x+16 [#permalink] New post   16 Sep 2019, 04:40
If i factorize f(x)=3x2−15x+16 , getting b^2-4ac = √33 .means solution will not give real values
but applying formula , it seems we have real solution −b/a= 5

can someone explain?
avatar
pranab223
Retired Moderator
Joined: 20 Apr 2016
Posts: 1307
Own Kudos [?]: 2281 [0]
Given Kudos: 251
WE:Engineering (Energy and Utilities)
Send PM

Top Member of the Month
Re: f(x)=3x^2−15x+16 [#permalink] New post   16 Sep 2019, 05:47
1
greMS15 wrote:
If i factorize f(x)=3x2−15x+16 , getting b^2-4ac = √33 .means solution will not give real values
but applying formula , it seems we have real solution −b/a= 5

can someone explain?



Can you plz check the link https://www.mathwarehouse.com/quadratic/roots/formula-sum-product-of-roots.php

and identify where u went wrong.
avatar
greMS15
Manager
Manager
Joined: 21 Oct 2015
Posts: 64
Own Kudos [?]: 48 [0]
Given Kudos: 0
Send PM
Re: f(x)=3x^2−15x+16 [#permalink] New post   16 Sep 2019, 08:52
I do not know what i have to look for in this link

pranab01 wrote:
greMS15 wrote:
If i factorize f(x)=3x2−15x+16 , getting b^2-4ac = √33 .means solution will not give real values
but applying formula , it seems we have real solution −b/a= 5

can someone explain?



Can you plz check the link https://www.mathwarehouse.com/quadratic/roots/formula-sum-product-of-roots.php

and identify where u went wrong.
User avatar
D
Carcass
Verbal Expert
Joined: 18 Apr 2015
Posts: 30492
Own Kudos [?]: 36853 [1]
Given Kudos: 26106
Send PM
Re: f(x)=3x^2−15x+16 [#permalink] New post   16 Sep 2019, 08:59
1
Expert Reply
This

Attachment:
shot26.jpg
shot26.jpg [ 145.02 KiB | Viewed 3108 times ]


it clears show to you how to solve a quadratic equations
avatar
greMS15
Manager
Manager
Joined: 21 Oct 2015
Posts: 64
Own Kudos [?]: 48 [0]
Given Kudos: 0
Send PM
Re: f(x)=3x^2−15x+16 [#permalink] New post   16 Sep 2019, 09:40
probably i am missing something obvious?

i am not able to factorize the equation 3x2−15x+16 :), i am getting solutions that is not real. b^2-4ac i am getting 33 , is that correct?



Carcass wrote:
This

Attachment:
shot26.jpg


it clears show to you how to solve a quadratic equations
User avatar
bumpbot
GRE Prep Club Legend
GRE Prep Club Legend
Joined: 07 Jan 2021
Posts: 5092
Own Kudos [?]: 76 [0]
Given Kudos: 0
Send PM
Re: f(x)=3x^2−15x+16 [#permalink] New post   10 Apr 2021, 21:40
Hello from the GRE Prep Club BumpBot!

Thanks to another GRE Prep Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
Prep Club for GRE Bot
gmatclubot
Re: f(x)=3x^2−15x+16 [#permalink]
10 Apr 2021, 21:40
Moderators:
adewale223
GRE Instructor
88 posts
bronaugust
GRE Forum Moderator
37 posts
BrushMyQuant
Moderator
1115 posts
VibhuAnurag
GRE Instructor
234 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Main navigation

Partners

GRE Resources

www.ets.org/gre | About | Terms and Conditions and Privacy Policy | Prep Club for GRE Rules | Contact