Can someone please help me solve this row reduction?
I need to figure out what steps to apply to solving this
2 -2 -3 : 1
5 2 1: 1
-1 5 4: 1
Thank you
I need to figure out what steps to apply to solving this
2 -2 -3 : 1
5 2 1: 1
-1 5 4: 1
Thank you
-
2 -2 -3 : 1
5 2 1: 1
-1 5 4: 1
this a 3X3 system with x, y, z
it's the same as:
2x - 2y - 3z = 1
5x + 2y + z = 1
- x + 5y + 4z = 1
when we have it in it's 'reduced row echelon form':
1 0 0 : x
0 1 0 : y
0 0 1 : z
you have it solved for some x, y, and z
2 -2 -3 : 1
5 2 1: 1
-1 5 4: 1
you have many options to get it into that form.
let R1 be row 1, etc...
change R3 to (R1 + 2R3)
2 -2 -3 : 1
5 2 1: 1
0 8 5: 3
change R1 to (R2 - 2R1)
1 6 7 : -1
5 2 1 : 1
0 8 5 : 3
change R2 to (R2 - 5R5)
1 6 7 : -1
0 -28 -34: 6
0 8 5 : 3
change R2 to (-1/2)R2
1 6 7 : -1
0 14 17: -3
0 8 5 : 3
notice in these last two matrices the second and third row (by themselves) are a 2X2 system...
change R3 to 4R2 - 7R3 (the lcm of 14 and 8 is 56)
1 6 7 : -1
0 14 17: -3
0 0 33 : -33
change R3 to (1/33)R3
1 6 7 : -1
0 14 17: -3
0 0 1 : -1
change R1 to R1 - 7R3
and
change R2 to R2 - 17R3
1 6 : -1
5 2 1: 1
-1 5 4: 1
this a 3X3 system with x, y, z
it's the same as:
2x - 2y - 3z = 1
5x + 2y + z = 1
- x + 5y + 4z = 1
when we have it in it's 'reduced row echelon form':
1 0 0 : x
0 1 0 : y
0 0 1 : z
you have it solved for some x, y, and z
2 -2 -3 : 1
5 2 1: 1
-1 5 4: 1
you have many options to get it into that form.
let R1 be row 1, etc...
change R3 to (R1 + 2R3)
2 -2 -3 : 1
5 2 1: 1
0 8 5: 3
change R1 to (R2 - 2R1)
1 6 7 : -1
5 2 1 : 1
0 8 5 : 3
change R2 to (R2 - 5R5)
1 6 7 : -1
0 -28 -34: 6
0 8 5 : 3
change R2 to (-1/2)R2
1 6 7 : -1
0 14 17: -3
0 8 5 : 3
notice in these last two matrices the second and third row (by themselves) are a 2X2 system...
change R3 to 4R2 - 7R3 (the lcm of 14 and 8 is 56)
1 6 7 : -1
0 14 17: -3
0 0 33 : -33
change R3 to (1/33)R3
1 6 7 : -1
0 14 17: -3
0 0 1 : -1
change R1 to R1 - 7R3
and
change R2 to R2 - 17R3
1 6 : -1