Question

let A= {x€z| x is a multiple of 5} and B={x€z | x is a divisor of 20} . Represent A,B and A' intersection B by the listing method and in a Venn diagram.

Answer 1

$$A=\{5k, k\in \mathbb{Z}\}, B=\{\pm1,\pm2,\pm4,\pm5,\pm10,\pm20\}$$

$$A'\cap B=\{\pm1,\pm2,\pm4\}$$