Question

Determinati valorile naturale ale lui x daca x multiplu de 5 iar (x+1)/40

Answer 1

x€M5
(x+1)|40 => x+1€D40
D40={1;2;4;5;8;10;20;40}
Cazuri:
1. 5|40=> x+1=5 => x=5-1 => x=4
2. 10|40=> x+1=10 => x=10-1 => x=9
3. 20|40 => x+1=20 => x=20-1 => x=19
4. 40|40 => x+1=40 => x=40-1 => x=39
Raspuns: x€{4;9;19;39}
Sper ca te-am ajutat!

Answer 2

din x multiplu de 5 => x apartine {0,5,10,15,20…..5n}

x+1 divide 40 => x+1 apartine D40

din  x+1 apartine {0,1,2,4,5,8,10,20,40} =>x apartine {0,1,3,4,7,9,19,39}

intersectam cele doua multimi si => x=0