Have you ever gone to the circus?

Ben enjoys watching T.V everyday.

I have lived in this house for five years.

The children are often afraid of crossing streets.

She always likes reading picture books in free time.

They are fond of listening to pop music everyday.

Ko

Tách nhỏ ra rồi mk làm bn

(3n + 7) ⋮ (2n + 3)

⇒ 2.(3n + 7) ⋮ (2n + 3)

⇒ (6n + 14) ⋮ (2n + 3)

⇒ (6n + 9 + 5) ⋮ (2n + 3)

⇒ [3.(2n + 3) + 5] ⋮ (2n + 3)

Để (3n + 7) ⋮ (2n + 3) thì 5 ⋮ (2n + 3)

⇒ 2n + 3 ∈ Ư(5) = {-5; -1; 1; 5}

⇒ 2n ∈ {-8; -4; -2; 2}

⇒ n ∈ {-4; -2; -1; 1}

     3n + 7 \(⋮\) 2n + 3 (n \(\in\) Z)

2.(3n + 7) ⋮ 2n + 3

6n + 14    ⋮ 2n + 3

3.(2n + 3) + 5 ⋮ 2n + 3

                   5 ⋮ 2n + 3

  2n + 3 \(\in\) Ư(5) = {-5; -1; 1; 5}

n \(\in\) {-4; -2; -1; 1}

33 arranging flowers interesting

34 about 2 hours each day doing my homework

35 collecting glass bottles is interesting

36 as dangerous as mountain climbing

37 To stay healthy you eat more vegetables and eat less high-fat food

38 Linh doesn't like playing board games 

39 Lan work less than Nam

40 Are you interested in listening to music

4.A

5.B

6.D

8.C

9.D

Abdcd

Vì | x+5 | >=0 với mọi x

    | y - 4 | >=0 với mọi y

=> |x +5| +|y-4|>=0

Mà |x+5|+|y-4|<=0 

=> \(\hept{\begin{cases}x+5=0\\y-4=0\end{cases}\Leftrightarrow}\hept{\begin{cases}x=-5\\y=4\end{cases}}\)

vậy ...........

hok tốt

Ta có: \(\hept{\begin{cases}\left|x+5\right|\ge0\forall x\\\left|y-4\right|\ge0\forall y\end{cases}}\)

\(\Rightarrow\left|x+5\right|+\left|y-4\right|\ge0\)

 \(\Rightarrow\left|x+5\right|+\left|y+4\right|=0\)

\(\Leftrightarrow\hept{\begin{cases}\left|x+5\right|=0\\\left|y-4\right|=0\end{cases}\Rightarrow\hept{\begin{cases}x+5=0\\y-4=0\end{cases}\Rightarrow}\hept{\begin{cases}x=-5\\y=4\end{cases}}}\)

vậy x =-5; y = 4

hok tốt!!

|x+5|+|y-4| < 0

Vì |x+5| > 0 (với mọi x)

     |y-4| > 0 (với mọi y)

=> |x+5|+|y-4| > 0

Mà |x+5|+|y-4| < 0

=> x+5=0 hoặc y-4=0

=      x=-5 hoặc     y=-4

Vậy x=5 hoặc y=-4

a) 2³.15 - [115 - (12-5)²]
= 8.15 - [115 - 7²]
= 120 - [115 - 49]
= 120 - 66
= 54
b) 30 : {175 : [355 - (135+37.5)]}
= 30 : {175 : [355 - (135 + 185)]}
= 30 : {175 : [355 - 320]}
= 30 : {175 : 35}
= 30 : 5
= 6
c) 12 : {390 : [500 - (125+35.7)]}
= 12 : {390 : [500 - (125+245)]}
= 12 : {390 : [500 - 370]}
= 12 : {390 : 130}
= 12 : 3
= 4

Bạn cần câu 2,3 hay 4?

2:a) nNaCl=0,5x58,5=29,25g

b)VH2(đktc)=0,4x22,4=8,96l

c)nFeO=7,2/72=0,1mol

d)nN2=6,72/22,4=0,3mol

3:

%mFe(trong FeO)=56/56+16.100%=77.78%

%mO(trong FeO)=16/56+16.100%=22.22%

4: khí N2 và khí O2:

\(\dfrac{MO2}{MN2}\)=\(\dfrac{32}{28}\)≈1,14

vậy khí O2 nặng hơn khí N2 xấp xỉ 1,14 lần

ai bảo thik hỏi nó cơ😀 😀 😀 😀 😀 😀

ngáo chó

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