a: \(\left|x-7\right|+13=25\)

=>|x-7|=12

=>x-7=12 hoặc x-7=-12

=>x=19 hoặc x=-5

b: 26-|x+9|=-13

=>|x+9|=39

=>x+9=39 hoặc x+9=-39

=>x=30 hoặc x=-48

`5 4/7:x-26=13`

`39/7:x=13+26`

`39/7:x=39`

`x=39/7:39`

`x=1/7`

Vậy `x=1/7`

cảm ơn nhanh kết bn fakeoob nói  chuyện

\(x+\dfrac{1}{3}=-\dfrac{7}{12}\\ \Rightarrow x=-\dfrac{7}{12}-\dfrac{1}{3}=-\dfrac{7}{12}-\dfrac{4}{12}=-\dfrac{11}{12}\)

\(x+\dfrac{1}{3}=\dfrac{7}{26}.\dfrac{-13}{6}\)

\(x+\dfrac{1}{3}=\dfrac{-91}{156}\)

\(x+\dfrac{1}{3}=\dfrac{-7}{13}\)

\(x=\dfrac{-11}{12}\)

[ ( 315 + 372 ) x 3 + ( 372 + 315) x 7 ] : ( 26 x 13 + 74 x 14 )

= [(315 +372)(3 + 7)] : (2.13.13 + 74.7.2)

= [687.10] : [2(169 +518)]

= 6870 : [2.687]

= 6870 : 1374 

= 5  

a) 12

b) 19

c) 15

d) 30

= [ 687 x 3 + 687 x 7 ] : 26 x 13 + 74 x 14 

= [ 687 x ( 3 + 7 ) ] : 26 x 13 + 74 x 14 

= [ 687 x 10 ] : 26 x 13 + 74 x 14 

= 6870 : 26 x 13 + 74 x 14

= 3435 + 1036

= 4471

= [ 687 x 3 + 687 x 7 ] : 26 x 13 + 74 x 14 

= [ 687 x ( 3 + 7 ) ] : 26 x 13 + 74 x 14 

= [ 687 x 10 ] : 26 x 13 + 74 x 14 

= 6870 : 26 x 13 + 74 x 14

= 3435 + 1036

= 4471

không biết

a)

x-3=15

x  = 15+3=18

b)

x+7-13=13

x+7     =13-13=0

x          = 0-7=-7

c) 

x+3-16=-4

x+3     =-4+16=12

x          = 12-3=9

d)

26-x-9=-13

     -x-9= -13-26=-39

      -x   =-39+9=-30

      x=30

\(\left|x+3\right|=15\)

\(\Rightarrow\orbr{\begin{cases}x+3=15\\x+3=-15\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=12\\x=-18\end{cases}}\)

vậy_

\(\left|x-7\right|+13=13\)

\(\Rightarrow\left|x-7\right|=0\)

\(\Rightarrow x-7=0\)

\(\Rightarrow x=7\)

vậy_

tt

\(=\frac{-1}{14}\)

\(=\frac{1}{14}\)

~~~~~ Chúc bạn học tốt ~~~~~

a/ \(x\left(x+7\right)=0\) \(\Rightarrow\left[\begin{matrix}x=0\\x+7=0\end{matrix}\right.\) \(\Rightarrow\left[\begin{matrix}x=0\\x=-7\end{matrix}\right.\)

b/ \(\left(-x+5\right)\left(3-x\right)=0\) \(\Rightarrow\left[\begin{matrix}-x+5=0\\3-x=0\end{matrix}\right.\) \(\Rightarrow\left[\begin{matrix}x=5\\x=3\end{matrix}\right.\)

c/ \(\left|x-1\right|=3\) \(\Rightarrow\left[\begin{matrix}x-1=3\\1-x=3\end{matrix}\right.\) \(\Rightarrow\left[\begin{matrix}x=4\\x=-2\end{matrix}\right.\)

d/ \(-13\left|x\right|=-26\) \(\Rightarrow\left|x\right|=2\) \(\Rightarrow x=\pm2\)

e/ \(x.x-8=-2.\left(-13\right)-\left(-2\right)\)

\(\Rightarrow x^2=36\) \(\Rightarrow\left|x\right|=6\) \(\Rightarrow x=\pm6\)