MathDB
Problems
Contests
National and Regional Contests
Turkey Contests
National Olympiad First Round
2005 National Olympiad First Round
22
22
Part of
2005 National Olympiad First Round
Problems
(1)
P22 [Number Theory] - Turkish NMO 1st Round - 2005
Source:
10/26/2013
For which
k
k
k
, there is no integer pair
(
x
,
y
)
(x,y)
(
x
,
y
)
such that
x
2
−
y
2
=
k
x^2 - y^2 = k
x
2
−
y
2
=
k
?
<
s
p
a
n
c
l
a
s
s
=
′
l
a
t
e
x
−
b
o
l
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′
>
(
A
)
<
/
s
p
a
n
>
2005
<
s
p
a
n
c
l
a
s
s
=
′
l
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t
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x
−
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>
(
B
)
<
/
s
p
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>
2006
<
s
p
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c
l
a
s
s
=
′
l
a
t
e
x
−
b
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d
′
>
(
C
)
<
/
s
p
a
n
>
2007
<
s
p
a
n
c
l
a
s
s
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
D
)
<
/
s
p
a
n
>
2008
<
s
p
a
n
c
l
a
s
s
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
E
)
<
/
s
p
a
n
>
2009
<span class='latex-bold'>(A)</span>\ 2005 \qquad<span class='latex-bold'>(B)</span>\ 2006 \qquad<span class='latex-bold'>(C)</span>\ 2007 \qquad<span class='latex-bold'>(D)</span>\ 2008 \qquad<span class='latex-bold'>(E)</span>\ 2009
<
s
p
an
c
l
a
ss
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
A
)
<
/
s
p
an
>
2005
<
s
p
an
c
l
a
ss
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
B
)
<
/
s
p
an
>
2006
<
s
p
an
c
l
a
ss
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
C
)
<
/
s
p
an
>
2007
<
s
p
an
c
l
a
ss
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
D
)
<
/
s
p
an
>
2008
<
s
p
an
c
l
a
ss
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
E
)
<
/
s
p
an
>
2009