Step-by-step explanation:
y=2x+9
y=6−x
(y-2x=9)(-1)
y+x=6
-y+2x=-9
3x=-3
x=-3/3=-1
sub x=-1 in eq 1
y-2(-1)=9
y+2=9
y=9-2=5
so (-1;5) is the only solution for this system
(hope it's correct)
