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If satisfies f(x-f(y))=f(f(y))+x f(y)+f(x)-1
MATHEMATICS · Subjective · AoPS · Mathematics · Functions · Functions
Problem
If
f
:
R
→
R
f:\mathbb{R}\to\mathbb{R}
f
:
R
→
R
satisfies
f
(
x
−
f
(
y
)
)
=
f
(
f
(
y
)
)
+
x
f
(
y
)
+
f
(
x
)
−
1
,
for all
x
,
y
∈
R
,
f(x-f(y))=f(f(y))+x f(y)+f(x)-1,\text{ for all }x,y\in\mathbb{R},
f
(
x
−
f
(
y
))
=
f
(
f
(
y
))
+
x
f
(
y
)
+
f
(
x
)
−
1
,
for all
x
,
y
∈
R
,
then
−
f
(
10
)
7
\frac{-f(10)}{7}
7
−
f
(
10
)
is
…
…
…
…
…
\dots\dots\dots\dots\dots
……………
Related theory
Functions
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