(1)
http://zhidao.baidu.com/question/983055279191726059.html?push=core&group=1&hideOtherAnswer=true
(2)
0http://zhidao.baidu.com/question/1860581254978695347.html?oldq=1
(3)
36V 电压源两头往里看:
6 // 6 // (4 + 4 // 4) = 2Ω
I总 = 36 / 12 = 3A
I = 1.5A