Question

If matrix A is 3 by 4 and a3=5a1-4a2, find non zero z in N(A).

Answer 1

dont get question

Answer 2

a3 =5a1-4a2
5a1-4a2-a3 = 0
| 5 | | 0 |
[ a1, a2, a3, a4] | -4 | = | 0 |
| -1 | | 0 |
| 0 |
Therefore, ( 5, -4, -1, 0) is one of the non zero answer in N(A)
Obviously, for any real constant, c, (5c, -4c, -1c, 0) is also a non zero answer in N(A)