Use ∈ or ∉ to fill in the gap. 𝑗 either is an element or is not an element in the set 𝑙, 𝑦, 𝑎.
We have two different options here. The first one is an element and the second one is not an element. Which means, we need to answer the question: is 𝑗 an element of the set 𝑙, 𝑦, 𝑎? No, 𝑗 is not part of this set because it’s not listed. And that means we fill in our blank with ∉.
𝑗 is not an element, is not contained in the set 𝑙, 𝑦, 𝑎.