Respuesta :

Answer:

x=1

y=-1

Step-by-step explanation:

they have already isolated y in both equations

label both equations

y=-x............1

y=3x-4........2

sub 1 into 2

-x=3x-4

-x-3x=-4

-4x=-4

x=1........ 3

sub 3 into 1

y=-(1)

y=-1