Question

enumerati elementele multimilor urmatoare: a) A={x | x apartine N,x<20 si 5|(12+x)}.VA ROG MULT.AJUTORRR!!!

Answer 1

A={x | x apartine N,x<20 si 5|(12+x)}.

12 + x = 5k => x = 5k - 12

k = 3 => x = 15-12 = 3

k = 4 => x = 20-12 = 8

k = 5 => x = 25-12 = 13

k = 6 => x = 30-12 =18

A = {3 , 8 , 13 , 18}