X1 - X2 - X3 + X4 = 0 (1) X2 - X2 + X3 - 3X4 = 1 (2) 2X1 - 2X2 - 2X4 = 1 (3) (1) + (2): 2X1 - 2X2 - 2X4 = 1 X3 = 2X4 + 1/2 (5) (3) ==> X1 = X2 + X4 + 1/2 通解为: X1 = s + t + 1/2 X2 = s X3 = 2t + 1/2 X4 = t s, t 为任意值
X1=X2=任意值，X3=X4=-1/2
答：x1+x2-x3=0, 解 取x1,x2为自由未知量,则 x3=x1+x2, 令(x1,x2)=(1,0),或(0,1),则x3=1, 于是,基础解系为:(1,...详情>>
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