Question

Cum se face o ecuatie gen $\frac{x}{x-1}$ apartine lui Z.

Answer 1

x/(x-1) ∈  Z   => (x-1)| x
                          (x-1)|(x-1)

(x-1)|x-x+1

(x-1)|1  => x-1={-1,1}

1)x-1= -1 =>x= 0

2)x-1= 1 =>x= 2

x={0,2}