Question

Calculati suma elementelor multimii A ={x € N |4 <2x-4=<8}.S=

Answer 1

Rezolvăm sistemul de inecuații.
$\left \{ {{4\ \textless \ 2x-4} \atop {2x-4 \leq 8}}\ \textless \ =\ \textgreater \ \left \{ {{8\ \textless \ 2x} \atop {2x \leq 12}} \right. \ \textless \ =\ \textgreater \ \left \{ {{x\ \textgreater \ 4} \atop {x \leq 6}} \right. \right.$.
Prin urmare 4<x≤6 sau x∈{5,6}.
S=5+6=11