\(\left|2x-3\right|=3-2x\)

\(ĐK:x\le\dfrac{3}{2}\)

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

\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}\\0=0\left(đúng\right)\end{matrix}\right.\)

Vậy \(S=\left\{x\in R;x=\dfrac{3}{2}\right\}\)

Con mèo vằn vào tranh, to hơn cả con hổ...dễ mến.(ko chắc nha, nếu đúng thì đây là so sánh hơn kém)

Bài 1:

a) \(3\dfrac{4}{5}.\left(-1\dfrac{1}{2}\right)+3\dfrac{4}{5}.2\dfrac{1}{2}-1\dfrac{4}{7}\) 

\(=\dfrac{19}{5}.\left(\dfrac{-3}{2}+\dfrac{5}{2}\right)-\dfrac{11}{7}\) 

\(=\dfrac{19}{5}.1-\dfrac{11}{7}\) 

 \(=\dfrac{19}{5}-\dfrac{11}{7}\) 

\(=\dfrac{78}{35}\) 

b) \(\dfrac{3}{4}:\left(-2\dfrac{1}{2}\right)-\dfrac{4}{5}:\left(-2\dfrac{1}{2}\right)+1\dfrac{1}{4}:\left(-2\dfrac{1}{2}\right)\) 

\(=\left(\dfrac{3}{4}-\dfrac{4}{5}+\dfrac{5}{4}\right):\dfrac{-5}{2}\) 

\(=\dfrac{6}{5}:\dfrac{-5}{2}\) 

\(=\dfrac{-12}{25}\) 

c) \(\dfrac{4}{5}-\left[\dfrac{3}{5}.\left(\dfrac{-2}{3}-1\dfrac{1}{3}\right)+\dfrac{4}{7}\right]\) 

\(=\dfrac{4}{5}-\left[\dfrac{3}{5}.\left(\dfrac{-2}{3}-\dfrac{4}{3}\right)+\dfrac{4}{7}\right]\) 

\(=\dfrac{4}{5}-\left[\dfrac{3}{5}.-2+\dfrac{4}{7}\right]\) 

\(=\dfrac{4}{5}-\left[\dfrac{-6}{5}+\dfrac{4}{7}\right]\) 

\(=\dfrac{4}{5}-\left(\dfrac{-22}{35}\right)\) 

\(=\dfrac{10}{7}\)

Bài 2:

a) \(\left(\dfrac{3}{4}-x\right).\dfrac{1}{2}-\dfrac{4}{5}=1\dfrac{1}{5}\) 

            \(\left(\dfrac{3}{4}-x\right).\dfrac{1}{2}=\dfrac{6}{5}+\dfrac{4}{5}\) 

             \(\left(\dfrac{3}{4}-x\right).\dfrac{1}{2}=2\) 

                       \(\dfrac{3}{4}-x=2:\dfrac{1}{2}\) 

                       \(\dfrac{3}{4}-x=4\) 

                              \(x=\dfrac{3}{4}-4\) 

                              \(x=\dfrac{-13}{4}\) 

b) \(\dfrac{3}{4}-\dfrac{1}{4}.x=2\dfrac{1}{3}\) 

            \(\dfrac{1}{4}.x=\dfrac{3}{4}-\dfrac{7}{3}\) 

            \(\dfrac{1}{4}.x=\dfrac{-19}{12}\) 

                 \(x=\dfrac{-19}{12}:\dfrac{1}{4}\) 

                 \(x=\dfrac{-19}{3}\)

Bài 2:

c) \(\left(\dfrac{4}{8}+x\right):\dfrac{2}{5}-\dfrac{1}{3}=1\dfrac{2}{3}\) 

           \(\left(\dfrac{1}{2}+x\right):\dfrac{2}{5}=\dfrac{5}{3}+\dfrac{1}{3}\) 

           \(\left(\dfrac{1}{2}+x\right):\dfrac{2}{5}=2\) 

                       \(\dfrac{1}{2}+x=2.\dfrac{2}{5}\) 

                       \(\dfrac{1}{2}+x=\dfrac{4}{5}\) 

                              \(x=\dfrac{4}{5}-\dfrac{1}{2}\) 

                              \(x=\dfrac{3}{10}\)

=>1/2x4<x<30/6

=>2<x<5

=>x=3 hoặc x=4

=>Có 2 số

có 2 số

x=3 hoặc  4

3 or 4

Theo ĐLBT KL, có: m_Na2SO4 + m_BaCl2 = m_NaCl + m_BaSO4

⇒ m_BaCl2 = m_NaCl + m_BaSO4 - m_Na2SO4 = 11,7 + 23,3 - 14,2 = 20,8 (g)

Bạn tham khảo nhé!