Question

tìm xez sao cho:

19 chia hết cho x

23 chia hết cho x+1

12 chia hết cho x-1

Answer 1

19 chia hết cho x

x \(\in\) Ư_{( 19 )}

x \(\in\) { 1 ; 19 }

 

Answer 2

a) Ta có: \(19⋮x\)

\(\Leftrightarrow x\inƯ\left(19\right)\)

hay \(x\in\left\{1;-1;19;-19\right\}\)

Vậy: \(x\in\left\{1;-1;19;-19\right\}\)

b) Ta có: \(23⋮x+1\)

\(\Leftrightarrow x+1\inƯ\left(23\right)\)

\(\Leftrightarrow x+1\in\left\{1;-1;23;-23\right\}\)

hay \(x\in\left\{0;-2;22;-24\right\}\)

Vậy: \(x\in\left\{0;-2;22;-24\right\}\)

c) Ta có: \(12⋮x-1\)

\(\Leftrightarrow x-1\inƯ\left(12\right)\)

\(\Leftrightarrow x-1\in\left\{1;-1;2;-2;3;-3;4;-4;6;-6;12;-12\right\}\)

hay \(x\in\left\{2;0;3;-1;4;-2;5;-3;7;-5;13;-11\right\}\)

Vậy: \(x\in\left\{2;0;3;-1;4;-2;5;-3;7;-5;13;-11\right\}\)

Answer 3

x ∈ Z

a. 19 chia hết cho x

=> x ∈ \(\left\{-19;-1;1;19\right\}\)

b. 23 chia hết cho x+1

=> x+ 1 ∈ \(\left\{-23;-1;1;23\right\}\)

=> x ∈ \(\left\{-24;-2;0;22\right\}\)

c. 12 chia hết cho x-1

=> x-1 ∈ \(\left\{-12;-4;-3;-1;1;3;4;12\right\}\)

=> x ∈ \(\left\{-11;-3;-2;0;2;4;5;13\right\}\)