| x - 2 | + | x + 3 | = 5

| x - 2 | = | 2+ x |  ,     | x + 3 | = | 3 - x |

Ta có :

| x - 2 | + | x + 3 | = |2 + x | + | 3 - x | >=|2 + x + 3 - x | = | 5 |

=>| x - 2 | + | x + 3 | >= 5

Dấu ( = ) xảy ra khi :  ( 2 + x ).( 3 - x )>=0

TH1:

2 + x >= 0                                               3 - x >= 0 

  x     >= - 2                                                  x <=3

=> x rỗng

TH2:

2 + x <=0                                                 3 - x <=0

      x<=-2                                                      x>=3

=> 3 <= x <= - 2

Vậy 3 <= x <= - 2 thì | x - 2 | + | x + 3 | = 5

Đáp án:

25 What are you going to do this week?

26 We might go on holiday to the moon in the future

27 There will be a robot in my house

28 The room is very large

25.What are you going to do this week?

26.We might go on holiday to the moon in the future.

27.There will be have robot in my house.

28.The room is large

Chúc bạn học tốt✔✔

goes
leaves
gets up
plays
do you usually get
opens - closes
visit
study
don't feel like
have
does the train for HCM city leave
recognize
do you do 
comes back - want

lập bảng xét dấu là ra liền mà 

4P+5O₂-to>2P₂O₅

         0,2-------0,08 mol

n _P=\(\dfrac{6,4}{31}\)=\(\dfrac{32}{155}\) mol

n _O2=\(\dfrac{4,48}{22,4}=0,2mol\)

=>P dư 

m _{P dư} =\(\dfrac{9}{775}\).31=0,36g

=>m _P2O5= 0,08.142=11,36g

44 ban nhe