01 2= −( ) ( ) ( )+ + +1 1 1A B C+ + +2 2 2A B CP 1( ) (2 )2 ( ) (2...
3,0
1 2
= −
( ) ( ) ( )
+ + +
1 1 1
a b c
2
2
2
P 1
( ) (
2
)
2
( ) (
2
)
2
( )
2
0,75
a b c
2
2
2
1 1 1 1 1 1
a + + + b c + + + = � � a b + + + c � � a b c + + +
2 2 2 4
( a + 1 ) ( b + 1 ) ( c + 1 ) � � a + + + + + 1 b 3 1 c 1 � � � �
3
= a b c + + + 3 3 � �
3
� � � �
2 54
P a b c − a b c
V y ậ ( )
3
+ + + + + +
1 3
2 54 ( )
= ( )
3
t − t =
+ v i ớ t a b c = + + + 1 ( t > 1)
2 f t
= − + = =
f t f t t
2 162 4
/
/
( ) ; ( ) 0
( )
+ =
2
4