Answer:
x=-4y and y=-1/4x
Step-by-step explanation:
3x-9y=6x+3y
3x-6x-9y=3y
-3x-9y=3y
-3x=3y+9y
-3x=12y
x=12/-3y
x=-4y
-----------------
3x=6x+3y-(-9y)
3x=6x+3y+9y
3x=6x+12y
12y=3x-6x
12y=-3x
y=-3/12x
y=-1/4x