Show that each of the following systems of linear equations is consistent and also find their
Solution:
2x + 2y – 2z = 1
4x + 4y – z = 2
6x + 6y + 2z = 3
|A| = 2(14) – 2(14) – 2(0)
|A| = 0
So, A is singular. Thus, the given system is either inconsistent or it is consistent with infinitely many solution according to as:
(Adj A)x B≠0 or (Adj A)x B = 0
Cofactors of A are:
C11 = (– 1)1 + 18 + 6 = 14
C21 = (– 1)2 + 1 4 + 12 = – 16
C31 = (– 1)3 + 1 – 2 + 8 = 6
C12 = (– 1)1 + 2 8 + 6 = – 14
C22 = (– 1)2 + 1 4 + 12 = 16
C32 = (– 1)3 + 1 – 2 + 8 = – 6
C13 = (– 1)1 + 2 24 – 24 = 0
C23 = (– 1)2 + 1 12 – 12 = 0
C33 = (– 1)3 + 1 8 – 8 = 0
adj A =
=
Adj A x B =
Now, AX = B has infinite many solution
Let z = k
Then, 2x + 2y = 1 + 2k
4x + 4y = 2 + k
This can be written as:
Hence, |A| = 0 z = 0
Hence, The given equation doesn’t satisfy .