Describe in words the region of 3 represented by the inequalities. 1 ≤ x2 + y2 + z2 ≤ 7 The inequalities 1 ≤ x2 + y2 + z2 ≤ 7 are equivalent to 1 ≤ x2 + y2 + z2 ≤ 7 , so the region consists of those points whose distance from the____ is at least [1] and at most [√7] . This is the set of all points on or between ___ with radii [1, √7] (entered as a comma-separated list) and centers (x, y, z) = ____