Frustrated

[Monique]

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.

[NateTG]

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. ;)

[Monique]

ahhh see? these little simple things.. thanks NateTG!

I should be doing other things at 2 in the morning :grumpy:

[fourier jr]

monique is a cutie :blush: