If x+2y=2 and (x+y)2=9, what is the value of y?

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The equation x + 2y = 2 and (x + y)² = 9 leads to the conclusion that y can be 5, with the corresponding x value being -8. The solution process involves substituting x from the first equation into the second, resulting in (2 - y)² = 9. Taking the square root reveals two potential solutions due to the nature of square roots, which are (-8, 5) and (4, -1). The discussion highlights the importance of recognizing that every number has two square roots, which is crucial for solving such equations. Overall, the correct value of y is confirmed to be 5.
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If x+2y=2 and (x+y)2=9, what is the value of y?

And the answer is not -1.. what is the trick here that I'm missing? The answer is supposed to be 5.
 
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Monique said:
If x+2y=2 and (x+y)2=9, what is the value of y?

And the answer is not -1.. what is the trick here that I'm missing? The answer is supposed to be 5.

x+2y=2
so
x=2-2y
so
(x+y)^2=(2-2y+y)^2=(2-y)^2=9
square root of both sides:
\pm (2-y)=3
-3=2-y or 3=2-y
So the solutions (note the plural) are:
(-8,5) and (4,-1)

I'm guessing you forgot that every number has two square roots. ;)
 
ahhh see? these little simple things.. thanks NateTG!

I should be doing other things at 2 in the morning
 
monique is a cutie :blush:
 
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