مسألة النقل تابعة الفصل الثالث
http://www.youtube.com/watch?v=sdjErlCBOGs
firsthttp://www.youtube.com/watch?v=M4K6HYLHREQ
secondhttp://www.youtube.com/watch?v=2ACJ9ewUC6U
thirdhttp://www.youtube.com/watch?v=8AA_81xI3ikhttp://www.youtube.com/watch?v=0T0z8d0_aY4
fourth
