The first and the 2nd one are correct because x is 21 and y is 49
3 and 4 at wrong
Answer:
B
Step-by-step explanation:
it is a rectangle. each opposite sides ARE parallel but not every side is equal like a square so B
Lets say the 3x3 Matrix is
M = [1 5 2 ]
[1 1 7 ]
[0 -3 7 ]
We apply the Gauss-Jordan elimination method
(Procedure and result shown in the image below)