Question

    Tìm x :

1) 128 - 3 . ( x + 4 ) = 23

2) [ ( 6x + 39 ) : 7 ] . 4 = 12

3) ( x : 3 - 4 ) . 5 = 15

4) | x + 2 | = 0 

5) | x - 5 | = | - 7

6) | x - 3 | = 7 - ( -2 )

7) ( 3x - 2⁴ )  . 7³ = 2 . 7 ⁴

8 ) | x - 3 | = | 5 | + | -7 | 

9) ( 7 - x ) - ( 25 + 7 ) = -25

Answer 1

\(\left|x+2\right|=0\)

\(\Rightarrow x+2=0\)

\(\Rightarrow x=0-2\)

\(\Rightarrow x=-2\)

Answer 2

\(\left|x-5\right|=\left|-7\right|\)

\(\Rightarrow\left|x-5\right|=7\)

\(\Rightarrow\hept{\begin{cases}x-5=-7\\x-5=7\end{cases}}\Leftrightarrow\hept{\begin{cases}x=-7+5\\x=7+5\end{cases}}\Leftrightarrow\hept{\begin{cases}x=-2\\x=12\end{cases}}\)

\(\Rightarrow x\in\left\{-2;12\right\}\)

Answer 3

|x+2|=0

\(\Rightarrow\)x+2=0

\(\Rightarrow\)x= 0-2

\(\Rightarrow\)x= -2