Question

Tìm x Thuộc Z

x² + 2x + 9 chia hết cho x + 2

 

 

 

Can you tell me about your lover ?

Answer 1

\(x^2+2x+9⋮x+2\)

\(\Leftrightarrow x\left(x+2\right)+9⋮x+2\)

Dễ thấy \(x\left(x+2\right)⋮x+2\) nên \(9⋮x+2\)

\(\Rightarrow x+2\in\left\{1;9;-1;-9;3;-3\right\}\)

\(\Rightarrow x\in\left\{-1;7;-3;-11;1;-5\right\}\)