\(x^5+x^4+x+1=0\)

\(\Leftrightarrow x+1=0\)

hay x=-1

x:x*15-3,7=2,3

x:2*15-3,7=2,3

x:2*15=2,3+3,7

x:2*15=6

x:2=6:15

x*2=0,4

x=0,4:2

x=0,2

\(a,x-1⋮x-3\)

\(\Rightarrow x-3+2⋮x-3\)

\(\Rightarrow2⋮x-3\)

\(x-3=\left\{-2;-1;1;2\right\}\)

\(x=\left\{1;2;4;5\right\}\)

\(b,x+6⋮x-1\)

\(\Rightarrow x-1+7⋮x-1\)

\(\Rightarrow7⋮x-1\)

\(x=\left\{-6;0;2;8\right\}\)

\(c,x⋮x-5\)

\(x-5+5⋮x-5\)

\(5⋮x-5\)

\(x=\left\{0;4;6;11\right\}\)

\(x-\dfrac{4}{12}=-\dfrac{5}{6}\)

⇔\(x-\dfrac{1}{3}=-\dfrac{5}{6}\)

⇔\(x=-\dfrac{1}{2}\)

\(\Leftrightarrow x=-\dfrac{1}{2}\)

=>(x-4).6=12.(-5)

=>6x-24=-60

=>6x=-36

=x=-6

Ta có x*6*8=96

=>x*48=96

=>x    =96:48

=>x    =2

\(\dfrac{x}{5}=\dfrac{5}{6}-\dfrac{19}{30}\)

\(\Leftrightarrow\dfrac{x}{5}=\dfrac{25}{30}-\dfrac{19}{30}=\dfrac{6}{30}=\dfrac{1}{5}\)

\(\Leftrightarrow x=1\)

Ta có : \(\dfrac{x}{5}=\dfrac{5}{6}+\left(-\dfrac{19}{30}\right)=\dfrac{25}{30}-\dfrac{19}{30}=\dfrac{1}{5}\)

\(\Leftrightarrow5x=5\)

\(\Leftrightarrow x=1\)

Vậy ...

Ta có: \(\dfrac{x}{5}=\dfrac{5}{6}-\dfrac{19}{30}\)

\(\Leftrightarrow\dfrac{x}{5}=\dfrac{25}{30}-\dfrac{19}{30}\)

\(\Leftrightarrow\dfrac{x}{5}=\dfrac{6}{30}=\dfrac{1}{5}\)

hay x=1

Vậy: x=1

a) Để \(\frac{13}{x-1}\)là số nguyên thì 13 chia hết cho x-1

=> x-1 thuộc Ư (13)={-13;-1;1;13}
Ta có bảng

b) Có x+3=x-2+5

=> 5 chia hết cho x-2

=> x-2 thuộc Ư(5)={-5;-1;1;5}

Ta có bảng

c) 2x=2(x+2)-4

=> 4 chia hết cho x+2 hay x+2 thuộc Ư (4)={-4;-2;-1;1;2;4}

Ta có bảng

Bài 1: 

\(=\dfrac{-3-39}{42}+\dfrac{-6-11}{17}-\dfrac{1}{6}=-\dfrac{119}{48}\)

Bài 2: 

=>x:5=-13/20

hay x=-65/20=-13/4

x/30 + 4/5= 79/30

x/30 = 79/30 - 4/5

x/30= 11/6

11/6= 55/30

=> x= 55