Question

x - 2 là ước của 7. Tìm x

Answer 1

a-2∈Ư(7)={1;7;−1;−7}a+2∈Ư(7)={1;7;−1;−7}

$\Rightarrow a\in \left\{-1;5;-3;-9\right\}$

Vậy $a\in \left\{-1;5;-3;-9\right\}$ là giá trị cần tìm

Answer 2

\(\Rightarrow7:\left(x-2\right)\\ m\text{à}7:\left(\pm9-2\right)\\ 7:\left(\pm3-2\right)\\ 7:\left(\pm1-2\right)\\ 7:\left(\pm5-2\right)\\ \Rightarrow x=\pm9;\pm3;\pm1;5\pm\)

Answer 3

Do x - 2 là ước 7

\(\Rightarrow7⋮\left(x-2\right)\)

\(\Rightarrow x-2\in\left\{-1;1;-7;7\right\}\)

*) \(x-2=-1\)

\(x=-1+2\)

\(x=1\)

*) \(x-2=1\)

\(x=1+2\)

\(x=3\)

*) \(x-2=-7\)

\(x=-7+2\)

\(x=-5\)

*) \(x-2=7\)

\(x=7+2\)

\(x=9\)

Vậy \(x=-1;x=3;x=-5;x=9\)