1,6 -/x-0,2/=0

<=>/x-0,2/=1,6

=>x-0,2=1,6    hoặc x-0,2=-1,6

<=>x=1,6+0,2    ;    x=-1,6+0,2

<=>x=1,8          ;     x=-1,4

vậy 1,6 -/x-0,6/=0 khi x=1,8 hoặc x=-1,4

để 1,6 - |x - 0,2| = 0 thì |x - 0,2| =1,6

ta có 2 trường hợp:

TH1: x - 0,2 = 1,6 => x = 1,8

TH2: x - 0,2 = - 1,6 => x = - 1,4

1,6 x 25/32 - ( 2/3+4/5) : 11/5 

= (5/4 : 11/5) - ( 2/3 + 4/5 )

= 25/44 - 22/15

= -0,89(84) 

\(x\div\left(9\dfrac{1}{2}-\dfrac{3}{2}\right)=\dfrac{0,4+\dfrac{2}{9}-\dfrac{2}{11}}{1,6+\dfrac{8}{9}-\dfrac{8}{11}}\)

\(x\div\left(\dfrac{19}{2}-\dfrac{3}{2}\right)=\dfrac{\dfrac{28}{45}-\dfrac{2}{11}}{\dfrac{112}{45}-\dfrac{8}{11}}\)

\(x\div8=\dfrac{\dfrac{218}{495}}{\dfrac{872}{495}}\)

\(\Rightarrow x\div8=\dfrac{218}{495}\div\dfrac{872}{495}\)

\(x\div8=\dfrac{1}{4}\)

\(x=\dfrac{1}{4}\times8\)

\(x=2\)

Vậy \(x=2\)

a) \(\left|3,5-x\right|=1,3\)

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

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

\(\Rightarrow\left[{}\begin{matrix}x=2,2\\x=4,8\end{matrix}\right.\)

b) \(1,6-\left|x-0,2\right|=0,4\)

\(\Rightarrow\left|x-0,2\right|=1,2\)

\(\Rightarrow\left[{}\begin{matrix}x-0,2=1,2\\x-0,2=-1,2\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=1,2+0,2\\x=-1,2+0,2\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=1,4\\x=-1\end{matrix}\right.\)

\(\left|3,5-x\right|=1,3\)

\(\Rightarrow\left[{}\begin{matrix}3,5-x=1,3\Rightarrow x=2,2\\3,5-x=-1,3\Rightarrow x=4,8\end{matrix}\right.\)

\(1,6-\left|x-0,2\right|=0,4\)

\(\Rightarrow\left|x-0,2\right|=1,2\)

\(\Rightarrow\left[{}\begin{matrix}x-0,2=1,2\Rightarrow x=1,4\\x-0,2=-1,2\Rightarrow x=-1\end{matrix}\right.\)

\(\left|x-1,5\right|+\left|2,5-x\right|=0\)

\(\left\{{}\begin{matrix}\left|x-1,5\right|\ge0\\\left|2,5-x\right|\ge0\end{matrix}\right.\)

\(\Rightarrow\left|x-1,5\right|+\left|2,5-x\right|\ge0\)

Dấu "=" xảy ra khi:

\(\left\{{}\begin{matrix}\left|x-1,5\right|=0\Rightarrow x=1,5\\\left|2,5-x\right|=0\Rightarrow x=2,5\end{matrix}\right.\)

\(1,5\ne2,5\Rightarrow x\in\varnothing\)

a) \(\frac{27}{8}\times\frac{5}{7}\times\frac{8}{27}+\frac{2}{7}\)

\(=\frac{27\times5\times8}{8\times7\times27}+\frac{2}{7}\)

\(=\frac{5}{7}+\frac{2}{7}\)

\(=1\)

b) \(1,6\times\frac{25}{32}-\left(\frac{2}{3}+\frac{4}{5}\right):\frac{11}{5}\)

\(=\frac{8}{5}\times\frac{25}{32}-\left(\frac{2}{3}+\frac{4}{5}\right).\frac{5}{11}\)

\(=\frac{5}{4}-(\frac{10}{33}+\frac{4}{11})\)

\(=\frac{5}{4}-\frac{2}{3}\)

\(=\frac{7}{12}\)

chịu luôn rùi! !   phần b, mk ko tính nhanh đc! cho mk xin lỗi bn nhiều nha!

A= -8/5: (1+2/3)

 = -8/5:5/3

 = -8/5.3/5

 = -24/25

B= 7/5.15/49-22/15: 11/5

 = 3/7-2/5

 = 1/35

\(A=-1,6:\left(1+\frac{2}{3}\right)\)

\(A=-1,6:\frac{5}{3}\)

\(A=-\frac{24}{25}\)

\(B=1,4.\frac{15}{49}-\left(\frac{4}{5}+\frac{2}{3}\right):2\frac{1}{5}\)

\(B=\frac{135}{98}-\frac{2}{3}\)

\(B=\frac{209}{294}\)

\(A=-1,6:\left(1+\frac{2}{3}\right)\)

\(A=\frac{-8}{5}:\frac{5}{3}=-\frac{8}{5}.\frac{3}{5}=\frac{-24}{25}\)

\(B=\frac{7}{5}.\frac{15}{29}-\left(\frac{4}{5}+\frac{2}{3}\right):\frac{11}{5}\)

\(B=\frac{21}{29}-\left(\frac{12}{15}+\frac{10}{15}\right).\frac{5}{11}=\frac{21}{29}-\frac{22}{15}.\frac{5}{11}=\frac{21}{29}-\frac{2}{3}\)

\(B=\frac{63}{87}-\frac{58}{87}=\frac{5}{87}\)

Ta có\(4A=1,6+\frac{8}{9}-\frac{8}{11}=B\Rightarrow\frac{A}{B}=\frac{1}{4}\)

Vậy \(\frac{A}{B}=\frac{1}{4}\)

\(A=0,4+2/9-2/11 A=28/45-2/11 A=218/495 B=1,6+8/9-8/11 B=112/45-8/11 B=872/495 Tao là V.ANH đây\)