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- General GMAT Strategies - 7 videos (all free)
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## Comment on

Common GMAT Data Sufficiency Myths - Part II## hello again :)

another question, when we are dealing with a quadratic and we know that only positive numbers fulfil our conditions (for instance in geometry), could we skip the calculation in this case? or is it also possible to get 2 positive solution from a quadratic ?

## Yes, it's possible to get to

Yes, it's possible to get to two positive solutions to a quadratic equation.

Take, for example, x² - 5x - 6 = 0

Factor to get: (x - 2)(x - 3) = 0

So, x = 2 or x = 3

Cheers,

Brent

## Hello admin... From the

## Is this the question you're

Is this the question you're referring to: https://gmatclub.com/forum/if-x-and-y-are-positive-integers-what-is-the-... ?

If so, I'm not sure what you are asking. I don't have x = 1 and y = 1 as a solution anywhere in my answer (https://gmatclub.com/forum/if-x-and-y-are-positive-integers-what-is-the-...)

Can you please elaborate on your question?

Cheers,

Brent

## You assumed the statement is

## I believe you're referring to

I believe you're referring to the question that starts at 2:15 in the above video.

We're told that x and y are positive integers, and we want to determine the value of x.

STATEMENT 1 tells us that 10x + 5y = 15

When we simplify this equation, we get: 2x + y = 3

Keep in mind that, in Data Sufficiency questions, each statement is true, so it MUST be the case that 2x + y = 3

Since there is ONLY ONE pair of values that satisfy this equation (x = 1 and y = 1), we can be certain that x MUST EQUAL 1.

If you feel that x could have values other than 1, you must find a DIFFERENT pair of x and y values that satisfy the equation 2x + y = 3.

For example, you are suggesting that x could equal 2. However, in order to satisfy the given equation (2x + y = 3), we must find a POSITIVE value of y to go along with x = 2.

However, if x = 2, then y must equal -3, and -3 is not positive.

Does that help?

Cheers,

Brent

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