Question

Daca A = { x € Z | | x-1 | = 5 , atunci A = ?

Answer 1

$|x-1|=5 \\ =\ \textgreater \ \left \{ {{5=x-1} \atop {5=-(x-1)}} \right. \\ \\ \left \{ {{6=x} \atop {5=-x+1}} \right. \\ \\ \left \{ {{x=6} \atop {4=-x}} \right. \\ \\ \left \{ {{x=6} \atop {x=-4}} \right.$

x ∈ {6, -4}
A = {6, -4}