Inverse of square matrix:

The inverse is, hence the result of multiplying the scalar 1/D by each and every element in the preceding matrix. Note that this is not the matrix A, but is determined by using the elements from A in the manner shown below: the values on the diagonal are reversed, and the operator negation is used on the other two values.

Note that if the determinant D is 0, it will not be possible to find the inverse of the matrix A.

The unknowns are found by evaluating this matrix multiplication, and hence:

x₁ = -1 * 2 +  1 * 6 = 4

x₂ = 1 * 2 + (-1/2) * 6 = -1

This, obviously, is the similar solution as found by the intersection of the two lines.

To do this in a MATLAB, at first we would generate the coefficient matrix variable a and column vector b.

>> a = [1 2; 2 2];

>> b = [2;6];