8/14/2019 Chuyen e 2: Phng Trnh Va Bat

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Chuyen e 2:PHNG TRNH VA BAT PHNG TRNH

CHA GIA TR TUYET OITOM TAT GIAO KHOA

I. nh ngha va cac tnh chat c ban :neu x 0( x )

neu x < 0

=

x1. nh ngha:

11

x Rx

2. Tnh chat : 2 20 , x =x x a b a b+ + a b a b + . 0a b a b a b+ = + . 0a b a b a b = +

II. Cac nh ly c ban :

a) nh ly 1 : Vi A 0 va B 0 th : A = B A2 = B2

b) nh ly 2 : Vi A 0 va B 0 th : A > B A2 > B2

III. Cac phng trnh va bat phng trnh cha gia tr tuyet oi c ban & cach giai :

* Dang 1 : 22 BABA == , BABA ==

* Dang 2 :

=

=

22

0

BA

BBA ,

=

=

BA

BBA

0,

=

> , 0))(( >+> BABABA

* Dang 4:2

B 0A B

A B

><

<

<

8/14/2019 Chuyen e 2: Phng Trnh Va Bat

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* Dang 5:

>

22

0

0

BA

B

B

BA ,

B 0

A B B 0

A B A

B< >

IV. Cac cach giai phng trnh cha gia tr tuyet oi thng s dung :

* Phng phap 1 :Bien oi ve dang c ban

V du : Giai cac phng trnh sau :

1) xxxx 22 22 += 2) 0382232 22 =+++ xxxx 3) 3342 +=+ xxx

4)x

x1

32 = 5) 21

42

2=

+

+

x

x6)

2

2

110

13

2=

+

+

x

x7) 1212 22 +=+ xxxx

* Phng phap 2 : S dung phng phap chia khoang

V du : Giai cac phng trnh sau :

1) 432 =+ xx 2) 314

3+=

x

x

V. Cac cach giai bat phng trnh cha gia tr tuyet oi thng s dung :

* Phng phap 1 : Bien oi ve dang c ban

V du : Giai cac bat phng trnh sau :

1) 652 + 321

-------------------Het-----------------

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