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:
Each week we'll be posting several questions from The Official Guide for GMAT® Review, 13th Edition and then after couple of days we'll provide Official Answer (OA) to them along with a slution.
We'll be glad if you participate in development of this project: 1. Please provide your solutions to the questions; 2. Please vote for the best solutions by pressing Kudos button; 3. Please vote for the questions themselves by pressing Kudos button; 4. Please share your views on difficulty level of the questions, so that we have most precise evaluation.
Its D.. it should be.. 5y^2=X^2/2-2 _________________
Bole So Nehal.. Sat Siri Akal.. Waheguru ji help me to get 700+ score !
A) dividing by 3 on either side gives the same equation as given in question stem ==> 3* 10y^2=3(x^2-4) ==> 3* 10^y = 3(x + 2)(x - 2) ==> Q B) diving by 2 on both side ==> 2* 10y^2=2 * (x-2)(x+2) ==> Q C) taking 4 to right hand side and solving ==> 10y^2=x^2 - 4 ==> 10y^2 = (x+2)(x-2) ==> Q D) multiplying both side by 2 ==> 10y^2=2x^2-4 ==> left hand side can't be factored to (x-2)(x+2). Hence, this is NOT equivalent to equation given in Q stem. We can stop here and mark option D. E) multiply both sides by 10 ==> 10 y^2=10 *(x^2-4)/10 ==> 10 y^2=(x^2-4) ==> 10 y^2=(x+2)(x-2)
** basic formula which should be known prior to solving this question =====> (A^2 - B^2) = (A+B)(A-B)
Other method to solve this Q is by substituting the values. The best value to take for "x" is 2 as it will make right hand side of the equation ZERO. _________________
Re: Which of the following equations is NOT equivalent to 10y^2= [#permalink]
12 Sep 2012, 11:49
This post received KUDOS
Which of the following equations is NOT equivalent to 10y^2=(x+2)(x-2) ? (A) 30y^2=3x^2-12 (B) 20y^2=(2x-4)(x+2) (C) 10y^2+4=x^2 (D) 5y^2=x^2-2 (E) y^2=(x^2-4)/10
The original equation reduces to 10y^2 = x^2 -4 Option 1 - 3 times of equation Option 2 - 2 times of equation Option 3 - Same as original of equation Option 4 - Answer (Skip this option & jump to option 5, which in turn is right. Thus using POE this will be the answer. To cross check one can solve it) Option 5 - 1/10 times of equation Answer D
Hope it helps _________________
If you like my Question/Explanation or the contribution, Kindly appreciate by pressing KUDOS. Kudos always maximizes GMATCLUB worth-Game Theory
If you have any question regarding my post, kindly pm me or else I won't be able to reply