Răspuns:
Explicație pas cu pas:
A={1,2,4,5,10,20}
B={2,4,6,8,12.....5,10.15,20,25.....}
A∩B={2,4,5,10,20}
[tex]A = \left\{x\,|\, \frac{20}{x}\in \mathbb{N}\right\}[/tex]
[tex]\to x \in D_{20}^+ \Rightarrow x\in \{1,2,4,5,10,20\}[/tex]
[tex]B = \left\{x\,|\,x\in M_2 \,\,\text{sau}\,\,x\in M_5 \right\}[/tex]
[tex]\to x\in \{0,2,4,6,8,...\}\cup \{0,5,10,15,20,...\}[/tex]
Înseamnă că:
[tex]\boxed{A \cap B = \{2,4,5,10,20\}}[/tex]
