Question

tìm x                                    

a) 4x - 33 = -5           b) 2.x + 1/4 = 3/2          d) |x + 2/7| = 1/6

Answer 1

a) Ta có: 4x-33=-5

\(\Leftrightarrow4x=28\)

hay x=7

Vậy: x=7

Answer 2

b) Ta có: \(2x+\dfrac{1}{4}=\dfrac{3}{2}\)

\(\Leftrightarrow2x=\dfrac{5}{4}\)

hay \(x=\dfrac{5}{8}\)

Vậy: \(x=\dfrac{5}{8}\)

Answer 3

\(a)4x-33=-5\\ \Rightarrow4x=28\\ \Rightarrow x=7\)

Vậy x = 7

\(b)2x+\dfrac{1}{4}=\dfrac{3}{2}\\ \Rightarrow2x=\dfrac{5}{4}\\ \Rightarrow x=\dfrac{5}{8}\)

Vậy \(x=\dfrac{5}{8}\)

\(c)\left|x+\dfrac{2}{7}\right|=\dfrac{1}{6}\\ \Rightarrow\left[{}\begin{matrix}x+\dfrac{2}{7}=\dfrac{1}{6}\\x+\dfrac{2}{7}=\dfrac{-1}{6}\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=\dfrac{-5}{42}\\x=\dfrac{-19}{42}\end{matrix}\right.\)

Vậy \(x\in\left\{\dfrac{-5}{42};\dfrac{-19}{42}\right\}\)

Answer 4

d) Ta có: \(\left|x+\dfrac{2}{7}\right|=\dfrac{1}{6}\)

\(\Leftrightarrow\left[{}\begin{matrix}x+\dfrac{2}{7}=-\dfrac{1}{6}\\x+\dfrac{2}{7}=\dfrac{1}{6}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{-19}{42}\\x=\dfrac{-5}{42}\end{matrix}\right.\)

Vậy: \(x\in\left\{-\dfrac{19}{42};-\dfrac{5}{42}\right\}\)

Answer 5

a) 4x - 33 = -5

4x = -5+33

4x = 28

x = 28:4

x= 7

b) 2.x+1/4=3/2

2.x = 3/2-1/4

2.x = 5/4

x = 5/4 :2

x = 5/8

 

Answer 6

a/ 4x - 33 = -5

4x = -5 + 33

4x = 28

x = 28 : 4

x = 7

Answer 7

a) 4x-33=-5

    4x     =-5+33

    4x     =28

      x     =28:4

      x    =7

b) 2.x+\(\dfrac{1}{4}=\dfrac{3}{2}\) 

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

     2.x      \(=\dfrac{5}{4}\) 

        x      \(=\dfrac{5}{4}:2\) 

        x      \(=\dfrac{5}{8}\) 

d) \(\left|x+\dfrac{2}{7}\right|=\dfrac{1}{6}\) 

\(\Rightarrow x+\dfrac{2}{7}=\dfrac{1}{6}\) hoặc \(x+\dfrac{2}{7}=\dfrac{-1}{6}\) 

            \(x=\dfrac{-5}{42}\) hoặc \(x=\dfrac{-19}{42}\)