anla12 D.若记 1122-(1221a22a216a2= Dr,b,a22 -azb2ba22b,a11D2'aubz -b,a21二b2a21则当D≠0时该方程组的解为DD2x.X2DD82.1引言§2.1 引言 若记 1 12 1 22 12 2 2 22 1 , a b a a b D a b b − = = 11 11 2 1 21 2 21 1 2 , a a b b a D b a b − = = 11 12 11 22 12 21 21 22 , a a a a a a D a a − = = 则当 D  0 时该方程组的解为 1 2 1 2 , . D D x x D D = =