X1+X2+X3+X4=5 (1)X1-2X2-X3+4X4=-2 (2)2X1-3X2-X3-5X4=-2 (3)3X1+X2+2X3+11X4=0 (4)(1)+(2) (1)+(3) (1)x2-(4)2X1-X2+5X4=3 (5)3X1-2X2-X4=3 (6)-X1+X2-9X4=10 (7)(5)x2-(6) (5)+(7)X1+11X4=6 (8)X1-4X4=13 (9)(8)-...谢谢！看懂了。可题目要求是用克拉默法则解，现在又多了种解题方法。