I don’t understand these problems

Both E and F are sets.

E = {w | w ≤ 2}

means that E is the set of all numbers w satisfying the condition that w ≤ 2. In other words, E contains all real numbers less than and including 2.

Similarly,

F = {w | w > 9}

is the set of all real numbers strictly greater than 9.

The intersection of E and F, denoted E ∩ F, is the set that contains the overlap of the two sets, or all the numbers that are common to both sets. In this case, E ∩ F is the empty set; this is because all numbers small than 2 cannot be larger than 9, so E ∩ F = ∅.

The union of E and F, written as E ∪ F, is the set containing all elements from both sets. In interval notation, E = (-∞, 2] and F = (9, ∞), so E ∪ F = (-∞, 2] ∪ (9, ∞).

in simplified version   it would be x ≤-4

step-by-step explanation:

multiply each term in x ≤-4 by -1

28

step-by-step explanation:

because that's the answer