Question

if A=[1,-1,2
1,-2,3
3,-1,2]
Show that A^(-1)=(1/2)[-1,0,1
7,-4,-1
5,-2,-1]

Answer 1

inverse matrix

Answer 2

One way to show that A^-1 is the inverse is to mult A * A^-1 and see if you get I

another way is use Gauss-Jordan elimination on the augmented matrix
[ A | I ]
and use elimination to reduce A to I (which turns the I on the right-side into A inverse)

Answer 3

if we multiply a*a^-1 what should we get?
1 0 0
0 1 0
0 0 1 ?

Answer 4

yes. try it.

Answer 5

thanks!