Question

Determinati nr intregi x apartine in Z\{-1} pentru care 7 supra x-1 apartine in Z .

Answer 1

7/(x-1) ∈Z; x∈Z-{1}

=> x-1∈D7

x-1 ∈ {-7;-1;1;7}

=> x∈{-6; 0; 2; 8}