4x+9y+z=12 2x-3y-2z=1 x+y-5z=0

问题描述:

4x+9y+z=12 2x-3y-2z=1 x+y-5z=0

(1)4x+9y+z=12 (2)2x-3y-2z=1 (3)x+y-5z=0 推出:(4)3x+3y-15z=0 (5)9x+9y-45z=0(2)+(4) 得出:(6)5x-17z=1(5)-(1)得出:(7)5x-46z=-12(6)-(7)得出:29z=13 所以:z=13/29代入(6)得出:5x-17×(...