Question

repede va rog coroana

Answer 1

2. a. 7∈{3n+2;3n+3;3n+4}
7=3n+4⇔3n+4=7⇒3n=3⇒n=1;
b. {7n+3;3n+7}={112,248}
Deoarece 7n+3>3n+7 oricare ar fi n∈R si respectiv 112<248 atunci
7n+3=248⇒7n=245⇒n=35;
Daca n=35 atunci 3n+7=3·35+7=105+7=112=112;
c. 2 la x-1 ≤16⁴=2¹⁶ ⇔x-1≤16⇒x≤15 (x∈N stelat) ⇒x={15,14,13,....,1}
Cardinalul multimii A este 15 deci n=15.
d. (x+2)/70 unde x∈N stelat deci x+2∈D₇₀∈N={5,7,10,14,35,70}
x={3,5,8,12,33,68};