\(3\dfrac{2}{5}-\dfrac{2}{5}+2\)

\(=\dfrac{3\times5+2}{5}-\dfrac{2}{5}+2\)

\(=\dfrac{17}{5}-\dfrac{2}{5}+2\)

\(=\dfrac{15}{5}+2\)

\(=2+3=5\)

Xét tứ giác `ABCD` có :

\(\widehat{A}+\widehat{B}+\widehat{C}+\widehat{D}=360^0\)

\(\Rightarrow\widehat{C}+\widehat{D}=360^0-\widehat{A}-\widehat{B}\)

\(\Rightarrow\widehat{C}+\widehat{D}=360^0-60^0-90^0\)

\(\Rightarrow\widehat{C}+\widehat{D}=210^0\)

\(\Rightarrow\widehat{C}=210:\left(3+4\right).3=90^0\)

\(\widehat{D}=210-90=120^0\)

Vậy....

Cho xin lỗi, lỡ chơi ngu >:

Bạn chịu khó gõ ra được không ạ ?

Uk

`1/2 : 2 xx x = 4`

`1/2 xx 1/2 xx x = 4`

`1/4 xx x = 4`

`x = 4 : 1/4`

`x = 4 xx 4`

`x = 16`

`#BaoL i n h`

`(254xx399-145)/(254+399xx253)`

` =((253 + 1)xx399 - 145)/(254+399xx253)`

` = (253 xx399 + 399-145)/(254 + 399 xx253)`

` = (253 xx 399 + 254)/(254 + 399 xx 253)`

` = 1`

`#BaoL i n h`

Quy luật :

`1 - 0 =1`

`4 -1 = 3`

`9 - 4 =5`

`=>` Số sau kém đơn vị số trước theo dãy số tự nhiên lẽ : `1,3,5,7,9,....`

Số tiếp theo :

`9 + 7 = 16`

`=> B`

`#BaoL i n h`

`2.(x - 51) = 2.2^3 + 20`

`2.( x - 51) = 2^4 + 20`

`2.(x -51) = 16 + 20`

`2.(x-51) = 36`

`x - 51 = 36 : 2`

`x - 51 = 18`

`x = 18 + 51`

`x = 69`                                                                  

______________________________________

`450 : ( x - 19) = 50`

`x - 19 = 450 : 50`

`x - 19  =9`

`x =9 + 19`

`x = 28`

__________________________________________

`4.(x -3) = 7^2 - 10^10`

`4.(x -3) = 49 - 1`

`4.(x-3) = 48`

`x - 3 = 48 : 4`

`x - 3 = 12`

`x = 12 + 3`

`x = 15`

_________________________________________

`#BaoL i nh`

Lần sau chụp có tâm xíu đi ạ!

`11/3 + | 1/2 - x | = 4`

`=> | 1/2 - x| = 4 - 11/3`

`=> | 1/2 - x |= 1/3`

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

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

\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{1}{6}\\x=\dfrac{5}{6}\end{matrix}\right.\)

Vậy,.......

`#BaoL i n h`