=1/4x12= 3

25%của12

=25%x12

=3

3

c: =>5x=40

hay x=8

⇔5x=6²+4

⇔5x=36+4

⇔5x=40

⇔x=8

Đây bạn!!!
c) 9x – 4x = 6¹⁷ : 6¹⁵ + 48 : 12
=> 5x = 6²+4
=> 5x = 36+4
=> 5x = 40
=> x = 8
 

\(M=\left(100-98\right)+\left(96-94\right)+...+\left(16-14\right)+12\\ M=2+2+...+2+12\\ \text{Tổng trên có }\left[\left(100-14\right):2+1\right]:2=22\left(\text{số hạng 2}\right)\\ \Leftrightarrow M=2\cdot22+12=44+12=56\)

(2x+1).(y2-5)=12=1.12=12.1=6.2=2.6=3.4=4.3=...(cả số âm)

Rồi bạn lập bảng

VD:

`(2x+1)(y^2-5)=12=1.12=(-1).(-12)=2.6=(-2).(-6)=3.4=(-3).(-4)`

  Vì `x;y` là số tự nhiên `=>x=1;y=3`

Áp dụng tính chất của DTSBN, ta được:

\(\dfrac{x}{4}=\dfrac{y}{5}=\dfrac{z}{6}=\dfrac{x-5z}{4-5\cdot6}=\dfrac{12}{4-30}=\dfrac{-12}{26}=\dfrac{-6}{13}\)

=>x=-24/13; y=-30/13; z=-36/13

Ta có 

\(\dfrac{x}{4}=\dfrac{y}{5}=\dfrac{z}{6}\)

Áp dụng tính chất dãy tỉ số bằng nhau :

\(\dfrac{x}{4}=\dfrac{y}{5}=\dfrac{z}{6}=\dfrac{x-5z}{4-5.6}=\dfrac{12}{-26}=-\dfrac{6}{13}\\ \Rightarrow\left\{{}\begin{matrix}x=-\dfrac{6}{13}\times4=-\dfrac{24}{13}\\y=-\dfrac{6}{13}\times5=-\dfrac{30}{13}\\z=-\dfrac{6}{13}\times6=-\dfrac{36}{13}\end{matrix}\right.\)

ta có : `x/4=y/5=z/6` và `x/4=y/5=(5z)/30` và `x-5z=12`

Áp dụng t/c dãy tỉ số bằng nhau ta có :

`x/4=y/5=(5z)/30 =(x-5z)/(4-30)=12/(-26)=-6/13`

`=>x/4 =-6/13=>x=-6/13 . 4=-24/13`

`=>y/5 =-6/13=>y=-6/13 . 5= -30/13`

`=>z/6=-6/13=>z=-6/13 . 6=-36/13`

vậy ...

\(=450\times\left(17+23\right)+450\times48+450\times12\\ =450\times\left(17+23+48+12\right)=450\times100=45000\)

45000

1 He is going to buy a new car

2 They are going to write a letter to thank him

3 I am going to visit Ha Long Bay

4 He is going to stop smoking

5 Linh is going to be a doctor

6 We are going to build a garage

7 She is going to clean the windows

8 They are going to invite lots of people

9 You are going to get wet

10 I am going to be sick

1 Where are you going 

2 Who did you go with

3 Do I know

4 What does she look like

5 How old is she

6 Do you want

A

A

A

TTổng là:

    5 0+ 7 0 + 9 0 = 210

            Đáp số:210

Tổng là 210

50+70+90

=120+90

=210

ok

ok

ủng hộ nhé