Bài 5.5:

\(\left(2x-3\right)\left(x+1\right)+\left(4x^3-6x^2-6x\right):\left(-2x\right)=18\)

\(\Leftrightarrow\left(2x^2+2x-3x-3\right)+2x\cdot\left(2x^2-3x-3\right):\left(-2x\right)=18\)

\(\Leftrightarrow2x^2-x-3-2x^2+3x+3=18\)

\(\Leftrightarrow2x=18\)

\(\Leftrightarrow x=\dfrac{18}{2}\)

\(\Leftrightarrow x=9\) 

Ta có : \(3x+14\)\(⋮\)\(3x+1\)

\(\Rightarrow\)\(\left(3x+1\right)+13\)\(⋮\)\(3x+1\)

mà \(3x+1\)\(⋮\)\(3x+1\)

\(\Rightarrow\)\(13\)\(⋮\)\(3x+1\)

\(\Rightarrow\)\(3x+1\in\text{Ư}\left(13\right)\)

\(\Rightarrow\)\(3x+1\in\left\{1;13\right\}\)

\(\Rightarrow\)\(x\in\left\{0;4\right\}\)

3x³+10x²-5 chia hết cho 3x+1

<=>3x+1=0

<=>x=-1/3

nói ai vậy nguyễn kim kiết

`x(x+1)+3x+3`

`=x(x+1)+3(x+1)`

`=(x+1)(x+3)` là SNT thì

`x+1=1\or\x+3=1`

`+)x=0=>x(x+1)+3x+3=3` là SNT

`+)x=-2=>x(x+1)=-1` k là SNT

Vậy `x=0`

câu trả lời ngắn gon nhất là .................................................................................................................................................................................................................................................................................................................. tự làm nhé bạn

xssssaswadqƯDWqdwdwd

b,Ta có 3x+7:x-2=>3x-6+13:x-2=>3(x-2)+13:x-2=>13:x-2

Vì \(x\in N\Rightarrow x-2\in N\Rightarrow x-2\inƯ\left(13\right)=\left(1,13\right)\Rightarrow x\in\left(3,15\right)\)

\(A=\dfrac{3x-1}{x+2}\inℕ\left(x\inℕ;x\ne-2\right)\)

\(\Rightarrow3x-1⋮x+2\)

\(\Rightarrow3x-1-3\left(x+2\right)⋮x+2\)

\(\Rightarrow3x-1-3x-6⋮x+2\)

\(\Rightarrow-7⋮x+2\)

\(\Rightarrow x+2\in U\left(7\right)=\left\{1;7\right\}\)

\(\Rightarrow x\in\left\{-1;5\right\}\)

\(\Rightarrow x\in\left\{5\right\}\left(x\inℕ\right)\)

Em xem lại đề nhé, sao lại vừa n vừa x?

b)Ta có:|2x+1|=2x+1=-(2x+1)
=>2x+1=3x-2=>x+x+1=x+x+x-2=>1=x-2=>x=3

-(2x+1)=3x-2=>-(x+x+1)=3x-2=>x-x-1=3x+2=>-1=3x-2=>3x=1=>x không phải số tự nhiên

Vậy x=3