# Thread: Summation notation

1. Originally Posted by VonNemo19
You plugged 'em in right, but unfortunately arrived at the wrong answer. What did you do after that?

Look at my last post for a hint.
lol I have no idea what to do after that, and yup it can't be negative. Welll..... x^2 - 2xy + y^2 wouldn't have anything to do with it, would it?

2. Originally Posted by marie7
lol i have no idea what to do after that, and yup it can't be negative.
$(3)^2+(-6)^2+(5)^2+(-12)^2=?$
Originally Posted by marie7
Welll..... X^2 - 2xy + y^2 wouldn't have anything to do with it, would it?
No... But that's the sign of a mathematician - you noticed some squares, and then you started thinkin about how to simplify. Very good.

3. $(2+1)^2+(-3-3)^2+(10-5)^2+(-5-7)^2$ $=3^2+(-6)^2+5^2+(-12)^2=9+36+25+144=214.$

I am so done with this thread...

4. Okay I can see AlephZero's post. -6^2 is 36 not -36. Thanks a lot everyone

5. Originally Posted by marie7
I got -146 again! What am I doing wrong? lol
Haha. Take a breath, clear your mind......

$(2+1)=3$ Squre it and get 9

$(-3-3)=-6$ Square It and get +36

$(10-5)=5$ Square it and get 25

$-5-7=-12$ Square it and get +144

Add 'em up and whadduya get?

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