Question

OFER 30 DE PUNCTE
Scrieti elementele multimii :
A= { x | x apartine N, (x+2) | 50 si 3|x }
B= {x |x apartine N, (2x+3) | 18 }
C= {x|x apartine N, 4 mai mic sau egal cu 2x mai mic decat 10 si (2x+1) | 7}.

Answer 1

x+2 ∈ D50={1,2,5,10,25,50}/-2
x∈{-1,0,3,8,23,48}

3/x => x∈M3={0,3,6,9,12,18,21,24..} 
A={0,3,48}

2x+3∈D18={1,2,3,6,9,18,}/-3
2x∈{-2,-1,0,3,6,15}/:2
x∈{-1,-1/2,0,3/2,3,15/2}
x∈N => B={0,3}

4≤2x<10/:2
2≤x<5 => x∈{2,3,4}

2x+1∈D7={1,7}/-1
2x∈{0,6}/:2
x∈{0,3}  =>C={3}