299. Use matrix method to solve the following system of equations:
6x + y – 3z = 5
x + 3y – 2z = 5
2x + y + 4z = 8

The given equations are
6x + y – 3z = 5
x + 3 y – 2z = 5
2x + y + 4 z = 8

These equations can be written as
                      


Co-factors of the elements of first row of | A | are
       
i.e.  14, – 8, – 5 respectively.
Co-factors of the elements of second row of  are 
 

i.e. – 7, 30, – 4 respectively. 
Co-factors of the elements of third row of | A | are

i.e. 7, 9, 17 respectively.