\(\left|x\right|-7=9\Rightarrow\left|x\right|=16\)

\(\Rightarrow x=\pm16\)

\(9-25=\left(7-x\right)-\left(25+7\right)\)

\(9-25=7-x-25-7\)(tính chất mở ngoặc đôie dấu)

\(9-25=-x-25\)

\(\Rightarrow\)\(9=-x\)

\(\Rightarrow x=-9\)

Vậy x = - 9

\(a.\)

\(\left|x\right|-7=9\)

\(\Rightarrow\left|x\right|=9+7=16\)

\(\Rightarrow\left[{}\begin{matrix}x=16\\x=-16\end{matrix}\right.\)

\(b.\)

\(9-25=\left(7-x\right)-\left(25+7\right)\)

\(\Leftrightarrow9-25=7-x-25-7\)

\(\Rightarrow-16=-x-25\)

\(\Rightarrow-x=-16+25=9\)

\(\Rightarrow x=-9\)

a)15 - x = 7 - (-2)

15-x = 9

x = 15 - 9

x = 6

b) 11 - ( 15 + 11 ) = x - (25 - 9 )

11 - 26 = x - 16

-15 = x - 16

-15 + 16 = x 

1 = x

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

(7-x) - 32 = -16

(7-x) = -16 + 32

7-x = 16

x = 7-16

x = -9

a,11-(15+21)=x-(25-9)

      11-15-21=x-25+9

               -x=-25+9-11+15+21

               -x=9

                x=-9

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

    -16=7-x-32

      x=7-32+16

     x=-9

\(A)9-25=\left(7-x\right)-\left(25+7\right)\)

\(\Rightarrow9-25=7-x-25-7\)

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

\(\Rightarrow x=\left(7-7\right)+\left(25-25\right)-9\)

\(\Rightarrow x=0+0-9\)

\(x=-9\)

\(B)x-\left(17-x\right)=x-7\)

\(\Rightarrow x-17+x=x-7\)

\(\Rightarrow2x-17=x-7\)

\(\Rightarrow x=-7+17\)

\(x=10\)

9 – 25 = (7-x) – (25 + 7)

9 + (-25) = 7 – x – 25 – 7

-16 = 7 – x – 25 – 7

X = 7 – 7 – 25 + 16

x = -25 + 16

x = -9

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

- 16 = 7 - x - 32

x = 7 - 32 + 16

x = - 9

Ta có : 9-25=(7-x)-(25+7)

       => 9 - 25 = 7 - x - 32 

     => 9 - 25 + 32 = 7 - x ( t/c chuyển vế đổi dấu)

     => 16 = 7 - x

     => x = 7 - 16 =  - 9

Nhớ k

=>9-25=7-x-25-7

=>7-25-7-9+25

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

=>x=0+0-9

=>x=-9

\(9-25=\left(7-x\right)-\left(25+7\right)\)

\(-16=7-x-25-7\)

\(-16=7-25-7-x\)

\(-25-x=-16\)

\(x=-25-\left(-16\right)\)

\(x=\)\(-9\)

Vậy \(x=-9\)

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

=> 9-25 =7-x-25-7

=> 9=7-7-25+25-x

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

=>9=0-0-x

=>9=-x

=>x=-9

Vậy x=-9

-16=7-x-32

=> -16=-25-x

=> x=-25+16=-9

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

-16=7-x-32

-16=-x-25

x=-25+16

x=-9

Vậy x=-9