2= 0= 0+ - + =2 4 2 02 7 11 0- + - ==+ 2 +1 +1- 1 + + 1 ( 1)( 1)+...

2 -

²

= 0

+ - + =

2 4 2 0

2 7 11 0

- + - =

=

+ 2

+1

+1

- 1

+ +

1

( 1)( 1)

+ -

+ 2

+1

1

( ) 1 -

³

+ +

1

- 1

+ + + - - + +

2 ( 1)( 1) ( 1)

( 1)( 1)

- + +

-

( 1)( 1)

- + +

+ +

1

1

1

=

3

+ +

1

3

=

=

S u t m: OÀN TI N TRUNG - THCS Hoàng V n Th - N

2010

_{+ = -}

_{3 2 2}

.3 3= -

²

- 1

- 1

2

2

±

6

2