Respuesta :

y = -2x

sub in the other 2

x +2x + z = 6

3x + z = 6 ->(1)


2x -4x - z = 3

-2x - z = 3 -> (2)

sum them

x = 9

y = -2x = -18

z = -2x - 3 = -18 -3 = -21