Yes they are! The square root of 36 is 6 and the square root of 25 is 5.
First equation is: x - y = 12
x = 12 + y
Now, substitute this in 2nd equation,
2x - 3y = 27
2(12+y) - 3y = 27
24 + 2y - 3y = 27
-y = 27 - 24
y = -3
In short, Your Answer would be -3
Hope this helps!
It's a linear binomial because it has two terms (binomial) and one degree (linear).