Is called a = {x/x? +3X+2≥0}，B={x/mx？ -4x+m- 1 & gt； 0, m∈R}, if A∩B= empty set A∪B=A ∪ b = a, find the value range of m.

Solution: A = {1, 2}

∫A∩B = empty set, a ∪ b = a ∪ b = a.

B = empty set

∴mx？ -4x+m- 1 & gt； 0 no solution

∴4/2m