Question

b) 2x là bội của x-2

c) x+1 là ước của 1²+7

Answer 1

a, 2x la boi cua x - 2

\(\Rightarrow2x⋮x-2\)

\(\Rightarrow2x-4+4⋮x-2\)

\(\Rightarrow2\left(x-2\right)+4⋮x-2\)

\(\Rightarrow4⋮x-2\)

Answer 2

b)

\(2x⋮\left(x-2\right)\)

\(\Leftrightarrow2\left(x-2\right)+4⋮\left(x-2\right)\)

\(\Leftrightarrow4⋮\left(x-2\right)\Rightarrow\left(x-2\right)\inƯ\left(4\right)=\left\{\pm1;\pm2;\pm4\right\}\)

\(\Leftrightarrow x\in\left\{3;1;4;0;6;-2\right\}\)

Answer 3

\(1^2+7⋮\left(x+1\right)\)

\(\Leftrightarrow8⋮\left(x+1\right)\Rightarrow\left(x+1\right)\inƯ\left(8\right)=\left\{\pm1;\pm2;\pm4;\pm8\right\}\)

\(\Leftrightarrow x\in\left\{0;-2;1;-33;-5;7;-9\right\}\)