Show that each of the following systems of linear equations is consistent and also find their
2x + 3y = 5
6x + 9y = 15
The above system of equations can be written as
or AX = B
Where A = B =
and X =
|A| = 18 – 18 = 0
So, A is singular,Now X will be consistence if (Adj A)xB = 0
C11 = (– 1)1 + 1 9 = 9
C12 = (– 1)1 + 2 6 = – 6
C21 = (– 1)2 + 1 3 = – 3
C22 = (– 1)2 + 2 2 = 2
Also, adj A =
=
(Adj A).B =
=
Thus, AX = B will be infinite solution,
Let y = k
Hence,
2x = 5 – 3k or X =
x = 15 – 9k or X =
Hence, X = , Y = k