(x + 3)(x - 5)≤0-3 ≤ x ≤ 5所以A = {x |-3 ≤ x ≤ 5}因为 B是A的子集所以有两种情况情况一:B是空集此时 m - 2 ≥ 2m -3解得 m ≤ 1情况二:-3 ≤ m - 2 < 2m -3 ≤ 5 1 < m ≤ 4综上: m ≤ 4
A=={x|(x+3)·(x-5)≤0}={x|-3≤x≤5}∵B是A的子集∴m-2≥3 且 2m-3≤5解得 -1≤m≤4所以m的取值范围为{m|-1≤m≤4}