Name: POH

Who is asking: Other Level: All

Question:
1) Determinants by expansion by minors.

i)
| 1 2 1 2 1 |
| 1 0 0 1 0 |
| 0 1 1 0 1 |
| 1 1 2 2 1 |
| 0 1 1 0 2 |

2) Solve the given system of equations by determinants.Evaluate the determinants by expansion by minors

i)
2x + y + z = 6
x - 2y + 2z =10
3x - y - z = -2

ii)
x + 2y -z =6
y - 2z - 3t = 5t
3x - 2y + t =2
2x + y +z -t =0

Thank for your help and can you show me the working. Thank you sir

Hi,

You can evaluate a determinant using minors along any row or column. Looking at your determinant

I would expand along the second row in order to take advantage of the 3 zeros in that row. Thus

Now you need to expand each of the 4x4 determinants. Again I would expand along the second row in each case. This will give you six, 3x3 determinants. Expanding each, using minirs along a row or column wil give 2x2 determinants which you can evaluate.

Cheers,
Harley
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