Question

-2x+y=9, x+2y=3 elimination

Answer 1

−2x+y=9
−2x+y+−y=9+−y
−2x=−y+9
−2x−2=−y+9−2
x=12y+−92

Now, x+2y=3
x+2y+−2y=3+−2y
x=−2y+3

Hoped I helped!