- #1
Nylex
- 552
- 2
It won't work and I don't see what I'm doing wrong.
Find the solutions of the following system of linear equations:
x + 3y - z = 1
2x + y + 2z = 3
5x + z = 2
I put these into the form Ax = b, where
A = (1 3 -1)
(2 1 2 )
(5 0 1 )
x = (x)
(y)
(z)
b = (1)
(3)
(2)
I worked out det A = 20.
Cramer's rule says the solutions are given by:
x = (1/det A) | 1 3 -1 | => x = 1/10
| 3 1 2 |
| 2 0 1 |
y = (1/det A) | 1 1 -1 | => y = 9/10
| 2 3 2 |
| 5 2 1 |
z = (1/det A) | 1 3 1 | => z = 11/10
| 2 1 3 |
| 5 0 2 |
These solutions are wrong, where have I gone wrong?? Grr.
When I work out the answers algebraically, I get x = 1/5, y = 3/5 and z = 1. These are correct.
Find the solutions of the following system of linear equations:
x + 3y - z = 1
2x + y + 2z = 3
5x + z = 2
I put these into the form Ax = b, where
A = (1 3 -1)
(2 1 2 )
(5 0 1 )
x = (x)
(y)
(z)
b = (1)
(3)
(2)
I worked out det A = 20.
Cramer's rule says the solutions are given by:
x = (1/det A) | 1 3 -1 | => x = 1/10
| 3 1 2 |
| 2 0 1 |
y = (1/det A) | 1 1 -1 | => y = 9/10
| 2 3 2 |
| 5 2 1 |
z = (1/det A) | 1 3 1 | => z = 11/10
| 2 1 3 |
| 5 0 2 |
These solutions are wrong, where have I gone wrong?? Grr.
When I work out the answers algebraically, I get x = 1/5, y = 3/5 and z = 1. These are correct.