Consider the matrices
A
â–³
=
2 3
2 4
, b â–³
=
6
8
. (7)
1. Use the formula
A
−1 =
C
T
det A
, (8)
where C is the cofactor matrix of A, to compute the inverse of A. Compute xc = A−1
b.
2. Use the formula
xj =
det Bj
det A
, (9)
where
Bj
â–³
=
a1 . . . aj−1 b aj+1 an
(10)
to compute the solution of Ax = b. Note that xj is the jth component of x and ai
is the ith column
of A.