2 1 4- - +X X- - -X X3 1 1 2- - - - -3 1( 10)( 1 2) 3 1X X X X= =...

10 . 2 1 4- - +x x- - -3 1 1 2- - - - -3 1( 10)( 1 2) 3 1x x x x= =- =-P x x x x

( ) ( )

( )

- - - - + -2(10 )( 1 4) 2 1 2 2 5

2

2

x= + - - = + - - = + - -(3 2 2) (3 2 2) 3 2 2 3 2 2

4

4

4

3 2 2

4

3 2 23 2 2 3 2 2- +

b)

P 1 2

=> x=

^{1+ 2 ( 2 1)- - =2}

vì x>1 P = ... 

Câu II: