Question

x+9 chia hết x+4

 

Answer 1

\(\Leftrightarrow x+4\in\left\{1;-1;5;-5\right\}\)

hay \(x\in\left\{-3;-5;1;-9\right\}\)

Answer 2

\(\Leftrightarrow x+4+5⋮x+4\)

Mà \(x+4⋮x+4\)

\(\Rightarrow x+4\inƯ\left(5\right)\)

\(\Rightarrow x\in\left\{1;-9;-3;-5\right\}\)

Answer 3

\(x+9⋮x+4\\ \Rightarrow\left(x+4\right)+5⋮x+4\\ v\text{ì}x+4⋮x+4\)nên để \(x+9⋮x+4\)thì 5 phải chia hết x+4

\(\Rightarrow x+4\in\text{Ư}\left(5\right)=\left\{1;-1;5;-5\right\}\\ \Rightarrow x\in\left\{-3;-5;1;9\right\}\)

Answer 4

x = 3