EXAM V
(10 pts) 1. Use manual methods to multiply. (You may use your calculator to verify your answer.)
1 -1 0
4 0
2 -3 3
0 2
1 -2
(15 pts) 2. Use manual methods to find the inverse of the matrix, and use manual matrix multiplication to verify that it is the inverse matrix.
2 -1
- 4 3
(15 pts) 3. Use manual methods to find the determinant of the matrix. (You may use your calculator to verify your answer.)
2 -1 0
-3 0 4
0 -3 4
(15 pts) 4. Solve, using matrix row operations, and check your results:
x - 3y + z = 4
-x + 4y - 4z = 1
2x - y + 5z = -3
(10 pts) 5. Find the
area of the triangle whose vertices are (1,1), (4,4), and (-1,5).
(15 pts) 6. Solve the system of equations by any method, and check your solution:
x + z
= 4
y - 2z + w = -12
y - z = -5
2x +
w = -2
(10 pts) 7. A florist
wants to arrange a dozen flowers consisting of carnations and roses. Carnations
cost $0.75 each, and roses cost $1.50 each. Find how many of each she should
use in order for the arrangement to cost a total of $12.00.
(10 pts) 8. Use the
matrix of Problem 2 to make a cryptogram of the message GOOD JOB.