1. Check even answers p.76: Hint: One of the problems on p.76 has
(2, -7, 12)
(-5, 2, 4)
(1/2, -3/4, 1/5)
(-16, 24, 12)
28. 2π (show work!)
Hint: One of the problems on p.76 has
no solution. Why is there no solution??

2. The following problems from pages 82-84 were not possible:
#9, 12, 29, 39

3. Notes 2-5 Determinants & Inverses
Each square matrix has a determinant, which is a single numerical value. If the determinant is 0, then the inverse of the matrix does not exist (undefined)
2 x 2 determinant (2nd order)

4. 3 x 3 determinant (3rd order)
“expansion by minors” 4

5. I = Identity Matrices:
2nd order  I =
3rd order th order
I = I =

6. The product of a matrix (A) and its inverse is the identity matrix:
Determinant 6