+ = ⇔ = −0B C B C⇔ − − + = −23 33 7 2008 6 2009X X X(3 7 2008) 6 2009 = +1 13X3 1 0 6⇔ − − = ⇔X X = −6

2) - DE THI THU VA DAP AN CHI TIET 10 CHUYEN09 10 2) - DE THI THU VA DAP AN CHI TIET 10 CHUYEN09 10
Toán DE THI THU VA DAP AN CHI TIET 10 CHUYEN09 10
2)

+ = ⇔ = −

0

b c

b

c

⇔ −

−

+

=

−

2

3

3

3

7

2008

6

2009

x

x

x

(3

7

2008) 6

2009

=

+

1

13

x

3

1 0

6

⇔

− − = ⇔

x

x

=

−



6