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Mạnh Khôiliked an answer of question

20/08/2018 at 03:30

Mạnh Khôiliked an answer of question

17/05/2018 at 11:50

Mạnh Khôianswered a question

20/08/2018 at 04:57

1 , 00 = 1

The price of the pencil is :

$\left(1,10-1\right):2=0,05$ ( $ )

...

Mạnh Khôianswered a question

18/08/2018 at 13:34

My answer is : C ) 3

Mạnh Khôifollowed a question

17/08/2018 at 13:33

After Lina used the box, she ranks the box as shown. If each edge is 30cm long, find the area on the shadow region? Express your answer in 2 ways.

area geometry

Mạnh Khôiliked an answer of question

09/01/2018 at 15:34

Mạnh Khôianswered a question

14/08/2018 at 15:12

C . Moles are the slowest and largest

Mạnh Khôianswered a question

14/08/2018 at 14:04

Change : $1\dfrac{1}{2}=\dfrac{3}{2}$

Call that number is a

We have :

$a+\dfrac{3}{2}=\dfrac{3}{2}a$

$\Rightarrow\dfrac{3}{2}=\dfrac{1}{2}a$

$\Rightarrow a=\dfrac{3}{2}:\dfrac{1}{2}$

$\Rightarrow a=3$

So that number is 3

Mạnh Khôianswered a question

14/08/2018 at 13:47

Now : Bob is 30 years old and Bill is 20 years old

Mạnh Khôiliked an answer of question

04/08/2018 at 07:21

Mạnh Khôiliked an answer of question

04/08/2018 at 07:21

Mạnh Khôianswered a question

04/08/2018 at 07:16

$\left(3x-1\right)\left(x^2+2\right)=\left(3x-1\right)\left(7x-10\right)$

$\Leftrightarrow x^2+2=7x-10$

$\Leftrightarrow x^2+2-7x+10=0$

$\Leftrightarrow x^2-7x+12=0$

$\Leftrightarrow x^2-2.x.\dfrac{7}{2}+\left(\dfrac{7}{2}\right)^2-\dfrac{1}{4}=0$

$\Leftrightarrow\left(x-\dfrac{7}{2}\right)^2=\dfrac{1}{4}$

$\Leftrightarrow\left[{}\begin{matrix}x-\dfrac{7}{2}=\dfrac{1}{2}\\x-\dfrac{7}{2}=-\dfrac{1}{2}\end{matrix}\right.$

$\Leftrightarrow\left[{}\begin{matrix}x=4\\x=3\end{matrix}\right.$

So $\left[{}\begin{matrix}x=4\\x=3\end{matrix}\right.$

Mạnh Khôianswered a question

04/08/2018 at 07:09

We have :

$\dfrac{x-91}{37}+\dfrac{x-86}{42}+\dfrac{x-78}{50}+\dfrac{x-49}{79}=4$

$\Rightarrow\left(\dfrac{x-91}{37}-1\right)+\left(\dfrac{x-86}{42}-1\right)+\left(\dfrac{x-78}{50}-1\right)+\left(\dfrac{x-49}{79}-1\right)=0$

$\Rightarrow\dfrac{x-128}{37}+\dfrac{x-128}{42}+\dfrac{x-128}{50}+\dfrac{x-128}{79}=0$

$\Rightarrow\left(x-128\right)\left(\dfrac{1}{37}+\dfrac{1}{42}+\dfrac{1}{50}+\dfrac{1}{79}\right)=0$

But $\dfrac{1}{37}+\dfrac{1}{42}+\dfrac{1}{50}+\dfrac{1}{79}\ne0$

$\Rightarrow x-128=0$

$\Rightarrow x=128$

So the value of x is : $128$

Mạnh Khôifollowed a question

04/08/2018 at 01:43

1999 is the last year of the 20th century, the last year of the 21st century is the year

Mạnh Khôiliked an answer of question

03/08/2018 at 03:17

Mạnh Khôianswered a question

03/08/2018 at 16:13

$\dfrac{2x}{5}-0,5x=\dfrac{1-2x}{4}+0,25$

$\Leftrightarrow0,4x-0,5x=\dfrac{1-2x}{4}+\dfrac{1}{4}$

$\Leftrightarrow-0,1x=\dfrac{2-2x}{4}$

$\Leftrightarrow-0,1x.4=2-2x$

$\Leftrightarrow-0,4x=2-2x$

$\Leftrightarrow-0,4x+2x=2$

$\Leftrightarrow1,6x=2$

$\Leftrightarrow x=1,25$

So the value of x is 1 , 25

Mạnh Khôianswered a question

03/08/2018 at 15:47

$\dfrac{x}{3}-\dfrac{2x+1}{2}=\dfrac{x}{6}-x$

$\Leftrightarrow\dfrac{2x}{6}-\dfrac{3\left(2x+1\right)}{6}=\dfrac{x}{6}-x$

$\Leftrightarrow x=\dfrac{x}{6}-\dfrac{2x}{6}+\dfrac{3\left(2x+1\right)}{6}$

$\Leftrightarrow x=\dfrac{x-2x+3\left(2x+1\right)}{6}$

$\Leftrightarrow x=\dfrac{-x+6x+3}{6}$

$\Leftrightarrow x=\dfrac{5x+3}{6}$

$\Leftrightarrow6x=5x+3$

$\Leftrightarrow6x-5x=3$

$\Leftrightarrow x=3$

So the value of x is 3

Mạnh Khôianswered a question

20/07/2018 at 03:50

We have :

$\left\{{}\begin{matrix}x+2y+3z=6\\2x+3y+z=8\\3x+y+2z=10\end{matrix}\right.$

$\Rightarrow x+2y+3z+2x+3y+z+3x+y+2z=6+8+10$

$\Rightarrow6x+6y+6z=24$

$\Rightarrow6\left(x+y+z\right)=24$

$\Rightarrow x+y+z=4$

So, the value of x + y + z equals : $4$

Mạnh Khôianswered a question

18/07/2018 at 04:29

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