1. Section 7.2 & 7.3

2.  Row x Column ROW COLUMN

3. a x + b y = c d x + e y = f AB X

4. A∙X = B A -1 A -1 A -1 (A∙X) = A -1 (B) A -1 X = A -1 B

5.  2 nd, x -1  → EDIT  Enter in matrix A & B  2 nd, x -1  Select Matrix [A]  Press x -1  2 nd, x -1  Select Matrix [B]  ENTER

7.  A matrix with only leading 1’s and 0’s everywhere else

8. a x + b y = c d x + e y = f 1. 2 nd, x -1 → MATH 2. rref([A])

9. x = r y = s

11. -2 2 -4 -3 -2R 1 + R 2

12. R 1 + R 3

13. Switch R 2 and R 3

14. 0 -3 3 -12 -3R 2 + R 3

15. - ½ R 3

16. 1. y = -2x + 4 2. 5x + 2y = 8 y = -2x - 1 x – y = 10 3. 2x + y = 2 4. y = -2x – 4 -2x + 2y = 10 5x + 3y = -6 { { { { Substitution Matrices EliminationGraphing