( x + 4 ) . ( x - 5 ) = 0

x + 4 = 0

x       = 0 - 4

x       = -4

hoặc

x - 5 = 0

x      = 0 + 5

x      = 5 ( loại )

Vậy x = -4

Học tốt nhé bạn !!

suy ra x+4=0 hoặc x-5=0

                x=-4           x=5

mà 8 chia hết cho x và x<0 suy ra x=-4

chúc bạn học tốt 

\(2x-10=-2x+14\)

\(\Rightarrow2x+2x=14+10\)

\(\Rightarrow4x=24\)

\(\Rightarrow x=24:4\)

\(\Rightarrow x=6\)

\(A=\frac{2n+7}{3n-1}\)

\(\Rightarrow3A=\frac{6n+14}{3n-1}=\frac{2\left(3n-1\right)+16}{3n-1}=2+\frac{16}{3n-1}\)

Để n là số nguyên 

\(\Rightarrow16⋮3n-1\)

\(\Rightarrow3n-1\in\left\{\pm1;\pm2;\pm4;\pm8;\pm16\right\}\)

Xét bảng

Vậy................................

p/s : ko chắc nha 

\(13⋮\left(x-2\right)\)

\(\Rightarrow\left(x-2\right)\inƯ\left(13\right)=\left\{\pm1;\pm13\right\}\)

\(\Rightarrow x\in\left\{3;1;15;-11\right\}\)

\(13⋮x-2\)

\(\Rightarrow x-2\inƯ\left(13\right)\)

\(\RightarrowƯ\left(13\right)=\left\{\pm1;\pm13\right\}\)

\(\Rightarrow x-2\in\left\{\pm1;\pm13\right\}\)

\(\Rightarrow x\in\left\{3;1;15;-11\right\}\)

\(4x+3⋮x-2\)

\(\Leftrightarrow4x-8+11⋮x-2\)

\(\Leftrightarrow11⋮x-2\)

\(\Rightarrow x-2\in\left(1;-1;11;-11\right)\)

\(\Rightarrow x\in\left(3;1;13;-9\right)\)

Vì \(x\in N\Rightarrow x=3;1;13\)

4^{44 nha} 

4^(4⁴) nha  hồi nãy nhầm

\(n-3⋮n-4\)

\(\Rightarrow\left(n-3\right)-1⋮n-4\)

\(\Rightarrow1⋮n-4\)

\(\Rightarrow n-4\inƯ\left(1\right)=\left\{\pm1\right\}\)

\(\Rightarrow n\in\left\{5;3\right\}\)

Vậy...............................