Source: Official Guide for the GMAT 13th Ed. Problem Solving; #37 Official Guide for the GMAT 2015 14th Ed. Problem Solving; #37

3

Which of the following equations is NOT

Which of the following equations is NOT equivalent to 10y = (x+2)(x-2)?

2 Explanations

1

SONIKA VASANTH

For answer choice D we can divide the equation by 2
so we get 5y^2=x^2-4/2
Which we can simplify as 5y^2=x^2-2?

Dec 4, 2016 • Comment

Sam Kinsman, Magoosh Tutor

Hi Sonika,

We have the equation 10y^2 = x^2 - 4. If we divide both sides by 2, we get:

5y^2 = ((x^2)/2) - 4/2
5y^2 = ((x^2)/2) - 2

Notice that this is not the same as answer choice D (5y^2=x^2-2), since the x^2 term is divided by 2. So we know that the equation we are working with is different from choice D, so choice D is correct.

Dec 7, 2016 • Reply

2

Gravatar Mike McGarry, Magoosh Tutor

Dec 27, 2013 • Comment

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Section 5.3 Problem Solving

Section 5.3 Problem Solving

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