解下列方程组: (1)(3x-y+z=10 (x+2y-z=6 (x+y+z=12 (2)(2x+4y+3z=9(3x-2y+5z=11(5x-6y+7z=13

问题描述:

解下列方程组: (1)(3x-y+z=10 (x+2y-z=6 (x+y+z=12 (2)(2x+4y+3z=9(3x-2y+5z=11(5x-6y+7z=13

(1)3x-y+z=10(1) x+2y-z=6 (2)x+y+z=12 (3)由(1)+(2)得4x+y=16(4)由(1)-(3)得2x-2y=-2x-y=-1(5)由(4)+(5)得5x=15x=3y=4z=5 (2)2x+4y+3z=9(1)3x-2y+5z=11 (2)5x-6y+7...