Question
Use matrix method to solve the following system of equations:
9x – 5y - 11z = 12
x – 3y + z = 1
2x + 3y – 7z = 2
Solution
The given equations are
9x – 5y – 11z = 12
x – 3y + z = 1
2x + 3y – 7z = 2
These equations can be written as
or 
Co-factors of the elements of first row of | A | are
Co-factors of the elements of second row of | A | are
i.e. – 68 – 41, – 37 respectively.
Co-factors of the elements of third row of | A | are
i.e. – 38, – 20, – 22 respectively.
Now,
