CÂU 7. CHỌN D. ( )2 5− 

5 : 5 2 7 5 17.

x

y

2

=

 ′ = −′ = → → = − − + = − +y tt y x x =

( ) ( ) ( )

( )

x y2 71− 

Ox Oy

∩

   

,

17 17 →   → =  + = ^. ;0 , 0 ;17 5 17 34A B P5 5