Hello, Mathgirl7!
Exactly where is your difficulty?
If you don't know matrix multiplcation,
. . very few of us are willing to teach it here.
. .
. . .
. .
Yes, they are inverses of each other.
1) Find the matrix product, if possible, please.
[ 6 0 -4 ] [1]
[ 1 2 5 ] [2]
[ 10 -1 3] [3]
2) Decide whether the given matrices are inverse of each other. ( Check to see if their product is the identity matrix 1:
[ 1 0 0 ] [1 0 0]
[ -1 -2 3 ] and [ 0 0 1]
[ 0 1 0] [1/3 1/3 2/3]
Thank you!