BÀI 5 X2 +4X +7 =(X+4) X2 7 X2 + 7 - X X2 7 4 X2 7 4X0  X27(...

1)

A

x

10 x

5

=

(

5)

10

5(

5)

x

25

25

25

25

x

x

x

x

5

x

5

(

5)

2

x

x

x

x

x

x

x

=

5

10

5

25

=

10

25

=

25

(

5)(

5)

=

5

5

 