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Problems
Contests
National and Regional Contests
Argentina Contests
Argentina National Olympiad
1995 Argentina National Olympiad
5
5
Part of
1995 Argentina National Olympiad
Problems
(1)
x^3+\sqrt{3}(a-1)x^2-6ax+b=0
Source: Argentina 1995 OMA L3 p5
5/13/2024
Let
a
,
b
a,b
a
,
b
be real numbers such that the equation
x
3
+
3
(
a
−
1
)
x
2
−
6
a
x
+
b
=
0
x^3+\sqrt{3}(a-1)x^2-6ax+b=0
x
3
+
3
(
a
−
1
)
x
2
−
6
a
x
+
b
=
0
has three real roots. Prove that
∣
b
∣
≤
∣
a
+
1
∣
3
|b|\leq |a+1|^3
∣
b
∣
≤
∣
a
+
1
∣
3
.>Clarification:
∣
x
∣
|x|
∣
x
∣
indicates the absolute value of
x
x
x
. For example,
∣
5
∣
=
5
|5|=5
∣5∣
=
5
;
∣
−
1.23
∣
=
1.23
|-1.23|=1.23
∣
−
1.23∣
=
1.23
; etc
algebra