Question 890227
plug in -1 for x and 3 for y
-a+3b=1+a
-2a+3b=1

-3a+6b=-2+b
-3a+5b=-2
-2a+3b=1

-3,5,-2
-2,3,1

determinant = 1
a= -11/1 = -11
b = -7/1 = -7

-3,5,-2
-2,3,1

divide row 1 by -3/1
1,5/-3,-2/-3
-2,3,1

add  down (2/1) *row 1 to row 2
1,5/-3,2/3
0,1/-3,7/3

divide row 2 by 1/-3
1,5/-3,2/3
0,1,-7

We now have the value for the last variable.
We will work our way up and get the other solutions.

add up  (-5/-3) *row 2 to row 1
1,0,-11
0,1,-7

final
1,0,-11
0,1,-7