Question

｛2x-y-z=3｛4x+2y-z=15｛4x+3y=18

Answer 1

2x-y-z=3 (1)

4x+2y-z=15 (2)

4x+3y=18 (3)

(2)-(1)

2x+3y=12 (4)

(3)-(4)

2x=6

x=3

y=(18-4x)/3=2

z=2x-y-3=1