Question

A={x∈Z|$\frac{9}{x-3}$∈Z}
B={x∈Z|6 se divide cu x sau 4 se divide cu x}
determinati cele doua multimi si calculati A∩B

Answer 1

x-3|9 <=> x-3 apartine {-9,-3,-1,1,3,9} <=> x apartine {-6,0,2,4,6,12}, deci A={-6,0,2,4,6,12}.

x|6 sau x|4 <=> x apartine {-6,-3,-2,-4,-1,1,2,3,4,6}, deci B={-6,-3,-2,-1,1,2,3,4,6}.

=> A intersectat B={-6,2,4,6}.