Question

Sa se determine multimeaA={„x apartineN /3x+19/x+3 apartine lui N

Answer 1

(3x+19)/(x+3) apartine lui N

=> x+3|3x+19

x+3|3(x+3)

x+3|3x+9

x+3|3x+19,  x+3 divide si diferenta lor

=>x+3|10

x+3={1,2,5,10}

x nr natural={2,7}

A={2,7}