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 GMAT 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.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 500,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

Statement 1: y = 0 This tells us that 0 = x² - 6x + 9 Factor the right side to get: 0 = (x - 3)(x - 3) So, it MUST be the case that x = 3 Since we can answer the target question with certainty, statement 1 is SUFFICIENT

Statement 2: x + y = 3 Rearrange this equation to get: y = 3 - x We're also told that y = x² - 6x + 9 So, it must be true that x² - 6x + 9 = 3 - x Rearrange to get: x² - 5x + 6 = 0 Factor: (x - 2)(x - 3) = 0 So, EITHER x = 2 OR x = 3 Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Re: If y = x^2 - 6x + 9, what is the value of x? [#permalink]

Show Tags

20 Jul 2016, 07:03

1

This post received KUDOS

GMATPrepNow wrote:

AbdurRakib wrote:

If y = x² - 6x + 9, what is the value of x?

(1) y = 0 (2) x + y = 3

Target question:What is the value of x?

Given: y = x² - 6x + 9

Statement 1: y = 0 This tells us that 0 = x² - 6x + 9 Factor the right side to get: 0 = (x - 3)(x - 3) So, it MUST be the case that x = 3 Since we can answer the target question with certainty, statement 1 is SUFFICIENT

Statement 2: x + y = 3 Rearrange this equation to get: y = x - 3 We're also told that y = x² - 6x + 9 So, it must be true that x² - 6x + 9 = x - 3 Rearrange to get: x² - 7x + 12 = 0 Factor: (x - 3)(x - 4) = 0 So, EITHER x = 3 OR x = 4 Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

From y = y^2 it follows that y(y - 1) = 0, so y = 1 or y = 0.

You cannot reduce y = y^2 by y because y can be 0 and we cannot divide by 0. By doing so you loose a root, namely y = 0.

Never reduce equation by variable (or expression with variable), if you are not certain that variable (or expression with variable) doesn't equal to zero. We cannot divide by zero.
_________________

From y = y^2 it follows that y(y - 1) = 0, so y = 1 or y = 0.

You cannot reduce y = y^2 by y because y can be 0 and we cannot divide by 0. By doing so you loose a root, namely y = 0.

Never reduce equation by variable (or expression with variable), if you are not certain that variable (or expression with variable) doesn't equal to zero. We can not divide by zero.

Oh yes! Noted, will keep that in mind. Thanks a lot Bunuel!

Re: If y = x^2 - 6x + 9, what is the value of x? [#permalink]

Show Tags

16 Jul 2017, 13:37

If \(y = x^2 - 6x + 9\), what is the value of x?

(1) \(y = 0\)

\(y = x^2 - 6x + 9\)

\(0 = x^2 - 6x + 9\)

\((x-3) (x-3) = 0\)

\(x = 3\)

Hence, (1) ===== is SUFFICIENT

(2) \(x + y = 3\)

\(y = 3 - x\)

\(y = x^2 - 6x + 9\)

\(3 - x = x^2 - 6x + 9\)

\(x^2 - 5x + 6 = 0\)

\((x - 3) (x - 2) = 0\)

\(x = 3\) Or

\(x = 2\)

Hence, (2) ===== is NOT SUFFICIENT

Hence, Answer is A

Did you like the answer? 1 Kudos Please _________________

"Nothing in this world can take the place of persistence. Talent will not: nothing is more common than unsuccessful men with talent. Genius will not; unrewarded genius is almost a proverb. Education will not: the world is full of educated derelicts. Persistence and determination alone are omnipotent."

Worried About IDIOMS?Here is a Daily Practice List: https://gmatclub.com/forum/idiom-s-ydmuley-s-daily-practice-list-250731.html#p1937393

Best AWA Template: https://gmatclub.com/forum/how-to-get-6-0-awa-my-guide-64327.html#p470475

The question is asking about the value of x, so X could not has two different values?

When a DS question asks about the value of some variable, then the statement(s) is sufficient ONLY if you can get the single numerical value of this variable.

In a Yes/No Data Sufficiency questions, statement(s) is sufficient if the answer is “always yes” or “always no” while a statement(s) is insufficient if the answer is "sometimes yes" and "sometimes no".

y = x^2 - 6x + 9 1) y=0 => y = x^2 - 6x + 9=0 => (x-3)^2 =0 => x=3 , single definite Ans A / D selected

2) x+y=3 or y=3-x => 3-x = y = x^2 - 6x + 9 => 3-x = x^2 - 6x + 9 => x^2-5x+6 =0 => (x-2)(x-3) =0 x=2 and x = 3 x=2,y=1 and if x=3,y=0 both are satisfying equation y = x^2 - 6x + 9 so x has 2 values => REJECTED D

ANSWER is A _________________

Give Kudos for correct answer and/or if you like the solution.