Question

解三元一次方程组，要详细过程，谢谢

解三元一次方程x-4y-z=-3.....①,2x+y-z=18....②x-y-z=7....③

Answer 1

x-4y-z=-3.....,2x+y-z=18 x-y-z=7....③
①*2-②得-9y-z=-13
①-③得-3y=-10
因此y=10/3
z=-17
x=-20/3