Math Question, hard

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• 12-02-2001
Yoshi
Math Question, hard
There is a question that I can never figure out why it is wrong. Here is the question:

16-36=25-45
= -20
16-36+20.25=25-45+20.25

FOIL / Complete the square...
(4-(9/2))^2 = (5-(9/2))^2
Sqrt it.
4-(9/2) = 5-(9/2)
4=5

why is it wrong?
This question held me prisoner for 5 hours and I just lost my last bit of hand-eye coordination.
---------------------------
Engineer223
• 12-02-2001
oskilian
well, I'll take a look at it, but I'm sure that the problem is with the sqrt.

you see, you can't do

a^2=b
a=sqrt(b)

that's not true, the solution is

a^2=b
a=(+/-)sqrt(b)

that's because 5^2=(-5)^2=25

but I'll give you the full answer in a while

Oskilian
• 12-02-2001
doubleanti
the trick is that when you square it, it can remove the negative... when you square it you are supposed to take the negative on the four and the positive on the five, thus giving you the difference... [+-0.5]
• 12-02-2001
oskilian
yup, that's it

Oskilian
• 12-02-2001
doubleanti
hasafraggin 3 minutes...
• 12-03-2001
What are you studying? I mean what grade.
• 12-03-2001
qwertiop
kindergarten.

j/k:)
• 12-03-2001
LOL, but don't be rude ;)
• 12-03-2001
*Michelle*
Haha, I got the a similar problem once...

y=root X (can't type the root sign)
is a function

y^2=X
(square both sides)
is not a function...
• 12-03-2001
y^2=X is a function.
• 12-03-2001
Yoshi
Another Question
What is the answer to (10˛ + 11˛ + 12˛ + 13˛ + 14˛) / 365 WITHOUT using your calculator.

Hint: {}
--------------------------
Engineer223

Midterm on Friday!!! ahhhh!!! [banging my head on the wall]
• 12-03-2001
Isometric
simple...2 :-)
and no I didnt use a calculator.
• 12-03-2001
oskilian
Quote:

y^2=X is a function.
no it isn´t, a function must have only one X value for each Y value, and this one doesn´t (for example: if X=4, y can be 2 or -2)

Oskilian
• 12-03-2001
Thantos
Ok here is one for you all.

y^x = x^y

x and y are not equal.
• 12-03-2001
Yoshi
x=4
y=2
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