1. Algebra 2 Adding and Subtracting Matrices

2. Algebra 2 The table shows information on ticket sales for a new movie that is showing at two theaters. Sales are for children (C) and adults (A). Lesson 4-2 Adding and Subtracting Matrices Theater C A C A 1 198 350 54 439 2 201 375 58 386 Matinee Evening a. Write two 2  2 matrices to represent matinee and evening sales. Theater 1 198 350 Theater 2 201 375 Matinee C A Theater 1 54 439 Theater 2 58 386 Evening C A Additional Examples

3. Algebra 2 (continued) Lesson 4-2 Adding and Subtracting Matrices b. Find the combined sales for the two showings. 198 350 201 375 + 54 439 58 386 = 198 + 54 350 + 439 201 + 58 375 + 386 = Theater 1 252 789 Theater 2 259 761 C A Additional Examples

4. Algebra 2 Find each sum. Lesson 4-2 Adding and Subtracting Matrices a.b. 9 0 –4 6 + 0 3 –8 –5 1 + –3 8 5 –1 = 9 + 0 0 + 0 –4 + 0 6 + 0 = 3 + (–3) –8 + 8 –5 + 5 1 + (–1) = 9 0 –4 6 = 0 Additional Examples

5. Algebra 2 A = and B =. Find A – B. Method 1: Use additive inverses. Lesson 4-2 Adding and Subtracting Matrices 4 8 –2 0 7 –9 4 5 A – B = A + (–B) = + 4 8 –2 0 –7 9 –4 –5 Write the additive inverses of the elements of the second matrix. 4 + (–7) 8 + 9 –2 + (–4) 0 + (–5) Add corresponding elements = –3 17 –6 –5 = Simplify. Additional Examples

6. Algebra 2 (continued) Method 2: Use subtraction. Lesson 4-2 Adding and Subtracting Matrices A – B = – 4 8 –2 0 7 –9 4 5 4 – 7 8 – (–9) –2 – 4 0 – 5 Subtract corresponding elements = –3 17 –6 –5 = Simplify. Additional Examples

7. Algebra 2 Adding and Subtracting Matrices Find each sum or difference. 2 8 0 –12 –9 6 6 –5 –3 1 4 8 –5 4 –3 –2 9 5 4 –6