\(x+20⋮x+1\)
\(\Rightarrow x+1+19⋮x+1\)
mà \(x+1⋮x+1\Rightarrow x+1\inƯ\left(19\right)=\left\{\pm1;\pm19\right\}\)
\(\Rightarrow x\in\left\{0;-2;18;-20\right\}\)
\(2x+10⋮2x+1\)
\(\Rightarrow2x+1+9⋮2x+1\)
\(\Rightarrow2x+1⋮2x+1\Rightarrow2x+1\inƯ\left(9\right)=\left\{\pm1;\pm3;\pm9\right\}\)
2x + 1 = 1 => x = 0
2x + 1 = -1 => x= -1
.... tương tự
\(30-5x⋮x\)
mà \(5x⋮x\Rightarrow x\inƯ\left(30\right)=\left\{\pm1;\pm2;\pm3;\pm5;\pm6;\pm10;\pm30\right\}\)
bn tự lập nha !