设集合A={x|-4＜x＜2},B={x|x²-3ax+2a²=0,x∈R},求使B包含于A的实数a的范围.

设集合A={x|-4＜x＜2},B={x|x²-3ax+2a²=0,x∈R},求使B包含于A的实数a的范围.
设集合A={x|-4＜x＜2},B={x|x²-3ax+2a²=0,x∈R},求使B包含于A的实数a的范围.

设集合A={x|-4＜x＜2},B={x|x²-3ax+2a²=0,x∈R},求使B包含于A的实数a的范围.
x²-3ax+2a²=0 (x-a)(x-2a)=0 x=a,x=2a
B包含于A
(1)a>0,a