38.x-x.12-x.16=40

<=> x(38-12-16)=40

<=> x.10=40

<=>x =4

\(Ta có: 38.x-x.12-x.16=40 \)

     \(\Rightarrow (38-12-16).x=40\)

     \(\Rightarrow 10.x=40\)

     \(\Rightarrow x=40:10\)

     \(\Rightarrow x=4\)

HOK TỐT...

Chọn đáp ắn đúng nhất (giúp mik giải thích cả 10 câu nha mn)

1. I think most children are creative enough to write .......... poems.

A. beautiful B. beautifully C. beauty D. beautify

2. It is necessary ............ forests.

A. protect B. protected C. to protect D. protecting

3. They made their living by .......... fish in the ocean every day.

A. catch B. to catch C. catching D. caught

4. I suggest.............. to the movies.

A. go B. going C. to go D. went

5. I have sent you a lot of letters but you have never been.....................

A. respond B. response C. responsive D. responsively

6. The cost of ............ is very high in big cities.

A. life B. live C. living D. lived

7. The next stage in the development of television is ...............TV.

A. interact B. interaction C. interactive D. interactively

8. By learning English, you can get access to the world’s...............

A. develop B development C. developed D. developing

9. Hurry up, or you won’t...................... the last bus.

A. miss B. take C. catch D. go

10. Let’s wait..............the rain stops.

A. before B. after C. until D. whe

1 A

2 C

3 C

4 B

5 C

6 C

7 C

8 B

9 C

10 C

\(\left|2x-3\right|=3-2x\)

\(ĐK:x\le\dfrac{3}{2}\)

\(\Leftrightarrow\left[{}\begin{matrix}2x-3=3-2x\\3-2x=3-2x\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}\\0=0\left(đúng\right)\end{matrix}\right.\)

Vậy \(S=\left\{x\in R;x=\dfrac{3}{2}\right\}\)

678*99+678

=678*99+678*1

=678*(99+1)

=678*100

=67800

33+34-230=số âm tiểu học chưa học

tích nha  Lê Thị Hoàng Linh

Tổng có 50 số hạng

Ta có:

(x + 1) + (x + 2) +...+ (x + 50) = 1475

(x + x +...+ x) + (1 + 2 +...+ 50) = 1475 (Tổng 1 có 50 số x)

50x + 1275 = 1475

=> 50x = 200

=> x = 4

(x+1)+(x+2)+(x+3)+....+(x+50)=1475

x50+ 1275                             =1475

x50                                       =1475-1275

x50                                       =200

x                                           =200:50

x                                           =4

60-[45+[2.7+1)]=0

60 - [45 + (2 . 7 + 1)]

=60 - [45 + (14 + 1)]

=60 - [45 + 15]

= 60 - 60

= 0

= 44

= 61 

TK MK NHA MK ĐG BỊ ÂM ĐIỂM

12 + 32 = 44

36 + 25 = 61

nha

719

vào câu hỏi tương tự tham khảo cách làm

kkkooo

mk nghĩ là trloi đúng và đc tích đúng á !!!

\(B=3^1+3^2+3^3+...+3^{300}\\=(3^1+3^2)+(3^3+3^4)+(3^5+3^6)+...+(3^{299}+3^{300})\\=3\cdot(1+3)+3^3\cdot(1+3)+3^5\cdot(1+3)+...+3^{299}\cdot(1+3)\\=3\cdot4+3^3\cdot4+3^5\cdot4+...+3^{299}\cdot4\\=4\cdot(3+3^3+3^5+...+3^{299})\)

Vì \(4\cdot(3+3^3+3^5+...+3^{299})\vdots2\)

nên \(B\vdots2\)

B=(3+3²)+(3³+3⁴)+...+(3²⁹⁹+3³⁰⁰)

B=3(1+3)+3³(1+3)+...+3²⁹⁹(1+3)

B=3.4+3³.4+...+3^299.4

B=4(3+3³+...+3²⁹⁹) chia hết cho 2 vì 4 chia hết cho 2

vậy B chia hết cho 2