10/8/12
1)Notes
2)Worksheet for practice
3)HW: Page 175 # 13, 14, 17, 18, 21, 24,
26, 34 AND continue work on your project
– DUE tomorrow!

Analyze Data with Matrices
A. Use the matrix below that includes information on tuition (T), room and board (R/B), and enrollment
(E) for three universities.
T R/B E
ISU
UI
UNI
Find the average of the elements in column 1, and interpret the result.

Analyze Data with Matrices
Answer: The average tuition cost for the three universities is $5935.

Analyze Data with Matrices
B. Use the matrix below that includes information on tuition (T), room and board (R/B), and enrollment
(E) for three universities.
T R/B E
ISU
UI
UNI
Which university’s total cost is the lowest?

Analyze Data with Matrices
ISU = 6160 + 5958 = $12,118
UI = 6293 + 7250 = $13,543
UNI = 5352 + 6280 = $11,632
Answer: University of Northern Iowa

Analyze Data with Matrices
C. Use the matrix below that includes information on tuition (T), room and board (R/B), and enrollment
(E) for three universities.
T R/B E
ISU
UI
UNI
Would adding the elements of the rows provide meaningful data? Explain.
Answer: No, the first two elements of a row are in dollars and the third is in numbers of people.

Analyze Data with Matrices
D. Use the matrix below that includes information on tuition (T), room and board (R/B), and enrollment
(E) for three universities.
T R/B E
ISU
UI
UNI
Would adding the elements of the third column provide meaningful data? Explain.
Answer: Yes, the sum of the elements of the third column would be the total enrollment of all three schools.

Answer:
Add and Subtract Matrices
Substitution
Add corresponding elements.
Simplify.

–
Add and Subtract Matrices
Answer: Since the dimensions of A are 2 × 3 and the dimensions of B are 2 × 2, these matrices cannot be subtracted.

C.
D.
A.
B.

C.
D.
A.
B.

Multiply a Matrix by a Scalar
Substitution

Answer:
Multiply a Matrix by a Scalar
Multiply each element by 2.
Simplify.

A.
C.
B.
D.

Multi-Step Operations
Perform the scalar multiplication first. Then subtract the matrices.
4 A – 3 B
Substitution
Distribute the scalars in each matrix.

Answer:
Multi-Step Operations
Multiply.
Subtract corresponding elements.
Simplify.

C.
D.
A.
B.

Use Multi-Step Operations with
Matrices
BUSINESS A small company makes unfinished desks and cabinets. Each item requires different amounts of hardware as shown in the matrices.
DESK CABINET
Nails
Screws
Short Long
Nails
Screws
The company has orders for 3 desks and
4 cabinets. Express the company’s total needs for hardware in a single matrix.

Use Multi-Step Operations with
Matrices
Write matrices.
Answer:
Nails
Screws
Short Long
Multiply scalars.
Add matrices.

Miniature golf course A has 50 blue golf balls, 100 yellow golf balls, and 50 green golf balls. Miniature golf course B has 150 blue golf balls, 100 yellow golf balls, and 25 green golf balls. Miniature golf course C has 40 blue golf balls, 70 yellow golf balls, and 80 green golf balls. Express the total number of each color golf ball in a single matrix.
B.
A.
Blue
Yellow
Green
Blue
Yellow
Green
C.
Course A
Course B
Course C
D.
Course A
Course B
Course C