Let A be a [img=41x19]1803c4e38325ee9.png[/img] matrix, then ________. A: If Ax=0 has only trivial solution, then Ax=b must have a unique solution. B: If Ax=0 has a nontrivial solution, then Ax=b must have infinitely many solutions. C: If Ax=b has a unique solution, then Ax=0 must have a unique solution. D: If Ax=0 has a nontrivial solution, then [img=55x23]1803c4e38c0c9df.png[/img] must have a nontrivial solution.

‎A is an [img=36x19]1803c4e61381e6b.png[/img] matrix and [img=12x14]1803c4e61b3a2fb.png[/img] is an n-dimensional column vector. If the [img=201x51]1803c4e628b33fd.png[/img], then the linear system ____________​‎​ A: [img=60x19]1803c4e6316cf85.png[/img] must have infinitly many solutions. B: [img=139x51]1803c4e63cf2009.png[/img]must have nontrivial solutions. C: [img=60x19]1803c4e6316cf85.png[/img] must have a unique solution. D: [img=139x51]1803c4e63cf2009.png[/img] only has nontrivial solutions.

关于扩展式表述信息集的说法，下面表述不正确的是（ ） A: 同一个信息集上的结点都是与同一个参与人相对应的 B: 某参与人的策略是该参与人在他所有信息集上确定的行动构成的行动序列 C: 包含两个或两个以上决策结点的信息集叫做非平凡的（Nontrivial）信息集 D: 博弈树上，同一个信息集不同结点发出的行动枝可以彼此不同