Diện tích hình tròn :

`6 xx 6 xx 3,14 = 113,04 (cm^2)`

D/s

`C`

chỉ cần `200 ->300` GP 1 môn là được làm hết ạ :>

`C1` 

`3/4 < 1`

`4/3 > 1`

`=> 3/4 < 4/3`

`C2`

`3/4 = 9/12`

`4/3 = 16/12`

Mà : `9 < 16`

`=> 3/4 < 4/3`

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`C1`

`11/8 > 1`

`7/10 < 1`

`=> 11/8 > 7/10`

`C2`

`11/8 = 110/80`

`7/10 = 56/80`

Mà : `110 > 56`

`=> 11/8 > 7/10`

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`#BaoL i n h`

`|1/5x-0,6|=|1/2x+0,4|`

`|1/5x-3/5|=|1/2x+2/5|`

\(\Rightarrow\left[{}\begin{matrix}\dfrac{1}{5}x-\dfrac{3}{5}=\dfrac{1}{2}x+\dfrac{2}{5}\\\dfrac{1}{5}x-\dfrac{3}{5}=\dfrac{2}{5}-\dfrac{1}{2}x\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}\left(\dfrac{1}{5}+\dfrac{1}{2}\right)x=\dfrac{3}{5}-\dfrac{2}{5}\\\left(\dfrac{1}{5}-\dfrac{1}{2}\right)x=\dfrac{2}{5}+\dfrac{3}{5}\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}\dfrac{7}{10}x=\dfrac{1}{5}\\-\dfrac{3}{10}x=1\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{1}{5}:\dfrac{7}{10}\\x=1:\dfrac{\left(-3\right)}{10}\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{1}{5}.\dfrac{10}{7}\\x=1.\dfrac{\left(-10\right)}{3}\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{2}{7}\\x=\dfrac{\left(-10\right)}{3}\end{matrix}\right.\)

Vậy....

`#BaoL i n h`

` x xx 1/2 = 6`

`x = 6 : 1/2`

`x = 6 xx 2`

`x =12`

`7/15 : 7/15 = 7/15 xx 15/7 = 105/105 = 1`

`|-2x+1/8|=|1/2-1/3|`

`|-2x+1/8|=|(-1)/6|`

`| -2x + 1/8| = 1/6`

\(\Rightarrow\left[{}\begin{matrix}2x-\dfrac{1}{8}=\dfrac{1}{6}\\-2x+\dfrac{1}{8}=\dfrac{1}{6}\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}2x=\dfrac{1}{6}+\dfrac{1}{8}\\-2x=\dfrac{1}{6}-\dfrac{1}{8}\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}2x=\dfrac{7}{24}\\-2x=\dfrac{1}{24}\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{7}{24}:2\\x=\dfrac{1}{24}:\left(-2\right)\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{7}{24}.\dfrac{1}{2}\\x=\dfrac{1}{24}.\dfrac{-1}{2}\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{7}{48}\\x=-\dfrac{1}{48}\end{matrix}\right.\)

Vậy.....

`#BaoL i n h`

`58 . 75 + 58 . 50 - 58 . 25`

`=58 . (75 + 50 - 25)`

` =  58 . 100`

` = 5800`

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` 27 . 39 + 27 . 63 - 2 .27`

` = 27 . (39 + 63 - 2)`

` = 27 . 100`

` = 2700`

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` 35 . 23 + 35 . 41 + 64 . 65`

` = 35 . ( 23 + 41) + 64 . 65`

` = 35 . 64 + 64 .65`

` = 64 . ( 35 + 65)`

` = 64 . 100`

` = 6400`

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`125 . 98 - 125 . 46 - 52.25`

` = 125 . ( 98 - 46) - 52.25`

` = 125 . 52 - 52 . 25`

` = 52 . (125 - 25)`

` = 52 . 100`

` = 5200`

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` 87 . 23 + 13 . 93 + 70 . 87`

` = 87 . 23 + 70 . 87 + 13 . 93`

` = 87 . (23 + 70) + 13 . 93`

` = 87 . 93 + 13. 93`

` = 93 . ( 87 + 13)`

` = 93 . 100`

` =9300`

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`#BaoL i nh`

Tổng độ dài hai đáy :

`270 xx 2 : 15 = 36 (cm)`

Tổng số phần bằng nhay :

`4 + 5 = 9 (phần)`

Đáy lớn :

`36 : 9 xx 5 = 20 (cm)`

Đáy bé :

`40 xx 4/5 = 16 (cm)`

Chiều cao `=` chiều rộng 

Đáy lớn `=` chiều dài 

Diện tích hình chữ nhật : 

` 15 xx 20 = 300 (cm^2)`

Diện tích phần mở rộng :

`300 - 270= 30 (cm^2)`

Đáp số...

`#BaoL i n h`