Ex. 1 Given matrixA, determinea_2,1,a_3,2, anda_1,3.

Solution: The value 4 is in the second row and the first column, so 4 is the 2,1-entry. That is, 4 =a_2,1(pronounced as "ay-sub-two-one"). The 3,2-entry is the value in the third row and the second column, soa_3,2= 8. Entrya_1,3is 3.

Answer: a_2,1= 4,a_3,2= 8,a_1,3= 3

1In matrix A in Ex. 1, find a_{3, 3}. Explain how you know.

2 In matrix A in Ex. 1, find a_{2, 3}. Explain how you know.

Ex. 3 Given matrixA, determine its dimensions

Solution: There are 3 rows and 3 columns which is called a square matrix.

Answer: The dimensions are 3 3 (a square matrix)

3In matrix A in Ex. 1, state the dimensions. Explain how you know.

4 In matrix A below, state the dimensions. Explain how you know.

-9 15Market 2 3 97 90 .95 W1 eggs 1.99 1.79 1.59 oranges Market N 3 W2 = 97 85 1.05 eggs 1.49 1.79 1.89 oranges