2x-y+2=8 y+2z=-2 3x+y-4z=1

2x-y+2=8 y+2z=-2 3x+y-4z=1

①X3-③X2得14z-5y=19④
將②④組成方程組
{y+2z=-2②
{14z-5y=19④
解,得y=23/12,z=24/9