How to solve x + y + Z = 17 2x-y-2z = 1 3x + y-4z = 3

How to solve x + y + Z = 17 2x-y-2z = 1 3x + y-4z = 3

x+y+z=17 2x-y-2z=1 3x+y-4z=3
x= 8,y= 3,z= 6