Verified answer

x² ≤ 4

x² - 4 ≤ 0

(x - 2)(x + 2) ≤ 0

++++++++[-2] ---------------- [2] ++++++++++

x∈ [-2, 2]

или

x² ≤ 4

|x|≤ 2

-2 ≤ x ≤ 2

x ∈ [-2, 2]