linera solver and cas

[Aries]

Solving by substitution, we have x=(1-2*y).
"Plugging" x=(1-2*y) into the other equation and solving for "y", we have:
2*(1-2*y)-a*y=2 --> 2-4*y-a*y=2 --> (-4-a)*y=0 --> y=0 (a<>-4).
Now "plugging" this y-value back into either equation and solving for "x", we have x=1.
Hence the Prime is correct.
Best,

Aries ;-)