Put in all the 1's
Erase the letters and the plus signs,
put a bar where the equal signs are,
and put the whole thing in parentheses:
The idea is to get all 0's below the diagonal.
Caution:
1. After you've finished getting zeros under the diagonal
in column 1, NEVER USE ROW 1 AGAIN!
2. After you've finished getting zeros under the diagonal
in column 2, NEVER USE ROW 2 AGAIN!
Multiply the Row 1 by -4
Add Row 1 to Row 2
Divide Row 1 by -4
Multiply Row 1 by 3
Add Row 1 to Row 3
Divide Row 1 by -3
Add Row 1 to row 4
Multiply Row 4 by 2
Add Row 3 to Row 4
Divide Row 3 by 2
Divide Row 4 by 2
Multiply Row 2 by 4
Multiply Row 3 by 11
Add Row 2 to Row 3
Multiply Row 4 by 3
Divide Row 2 by 4
Add Row 3 to Row 4
Now put the letters and the equal signs back in-
Erase all the 0's and the 1's
Solve the 4th equation for w
Substitute into the 3rd equation and solve for z
Substitute and into the 2nd
equation and solve for y:
Substitute , , and 
So the solution is (x,y,z,w) = (0,1,-2,4)
Edwin
