Question

[nguyen vu ly na]

tìm số tự nhiên x sao cho:

(3X+16)chia hết cho (x+2)

Answer 1

[Hà Hoàng Thịnh]

( 3x + 16 )\(⋮\)( x + 2 )

\(\Rightarrow\)3x + 16 = 3 ( x + 2 ) +10

\(\Rightarrow\)10\(⋮\)( x + 2 )

\(\Rightarrow\)x + 2 \(\in\)\(\left\{1;2;5;10\right\}\)

\(\Rightarrow\)x\(\in\left\{0;3;8\right\}\)

Answer 2

[A lovely girl]

\(\left(3x+16\right)⋮x+2\)

\(\Rightarrow3\left(x+2\right)+10⋮x+2\)

\(\Rightarrow10⋮x+2\Rightarrow x+2\inƯ\left(10\right)\)

Mà \(Ư\left(10\right)=\left\{1;2;5;10\right\}\)

\(\Rightarrow x+2\in\left\{1;2;5;10\right\}\)

\(\Rightarrow x\in\left\{-1;0;3;8\right\}\)

Vì \(x\in N\Rightarrow x\in\left\{0;3;8\right\}\)