Answer:
x = -1/3 , y = 3/2
Explanation:
Solve the following system: 
{4 - 4 y = -2 
-9 x - 4 y = -3 
 
Express the system in standard form: 
{0 - 4 y = -6 
-9 x - 4 y = -3 
 
Express the system in matrix form: 
(0 | -4 
-9 | -4)(x 
y) = (-6 
-3) 
 
Write the system in augmented matrix form and use Gaussian elimination: 
(0 | -4 | -6 
-9 | -4 | -3) 
 
Swap row 1 with row 2: 
(-9 | -4 | -3 
0 | -4 | -6) 
 
Multiply row 1 by -1: 
(9 | 4 | 3 
0 | -4 | -6) 
 
Divide row 2 by -2: 
(9 | 4 | 3 
0 | 2 | 3) 
 
Divide row 2 by 2: 
(9 | 4 | 3 
0 | 1 | 3/2) 
 
Subtract 4 × (row 2) from row 1: 
(9 | 0 | -3 
0 | 1 | 3/2) 
 
Divide row 1 by 9: 
(1 | 0 | -1/3 
0 | 1 | 3/2) 
 
Collect results: 
Answer: {x = -1/3 , y = 3/2