Question

解方程组x-2y=-9 y-z=3 2z+x=47

Answer 1

x-2y=-9-----------------①

y-z=3--------------------②

2z+x=47----------------③

①-③

-2y-2z=-9-47=-56-----④

y-z=3--------------------②

④-②X2

-4y=-56-6=-62

y=31/2

z=25/2

x=22