Question

tìm x ∈ N sao cho:

 

a) x + 6 chia hết cho x

 

b) x+ 9 chia hết cho x+1

c) 2x + 1 chia hết cho x - 1

Answer 1

a: =>6 chia hết cho x

=>\(x\in\left\{1;2;3;6\right\}\)

b: =>x+1+8 chia hết cho x+1

=>\(x+1\in\left\{1;2;4;8\right\}\)

hay \(x\in\left\{0;1;3;7\right\}\)

c: =>2x-2+3 chia hết cho x-1

=>\(x-1\in\left\{-1;1;3\right\}\)

hay \(x\in\left\{0;2;4\right\}\)