Lesson: Basic Equation Solving

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Comment on Basic Equation Solving

Hi Brent,
In your solution to this question
https://gmatclub.com/forum/if-x-y-2-x-2-y-2-then-which-one-of-the-following-statements-241756.html

Given: (x − y)² = x² + y²
(x − y) (x − y) = x² -xy -xy +y² --> x² -2xy +y² = x² + y²
How you got it x² - xy + y² = x² + y²
where is the 2 in -2xy, although it will disappear in the next steps when we divide by -2, but I am just curious why it disappeared before, or maybe I am missing something..
Thank you.
gmat-admin's picture

Good catch - thanks!!
I have edited my solution here: https://gmatclub.com/forum/if-x-y-2-x-2-y-2-then-which-one-of-the-follow...

Cheers,
Brent

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