1. EXAMPLE 1
Add and subtract matrices
Perform the indicated operation, if possible.
–5 –1 a.
–1 4
2 0 +
3 + (–1) – –1 + 0 = =
–3 –1 –
3 –10 –
0 –2
–1 6 b. –
7 – (–2) – 5
0 – –2 – (–10)
–1 – (–3) – 1 =
9 –1 – =

2. EXAMPLE 2
Multiply a matrix by a scalar
Perform the indicated operation, if possible. a.
4 –1
1 0
2 7 –2
–2(4) –2(–1)
–2(1) –2(0)
–2(2) –2(7) = – –
–4 –14 =
b. 4
–2 –8 – –5 +
4(–2) 4(–8) (5) (0)
–3 8
6 –5 = +
–8 –32
–3 8
6 –5 = +

3. EXAMPLE 2
Multiply a matrix by a scalar
–8 + (–3) –32 + 8
(–5) =
–11 –24 –5 =

4. GUIDED PRACTICE
for Examples 1 and 2
Perform the indicated operation, if possible. + –
4 – 1.
– –5
–2 –8 4
ANSWER –
2 –

5. GUIDED PRACTICE
for Examples 1 and 2 –
7 –2 – –
5 –14 2. –
ANSWER
– –2 –2 –

6. GUIDED PRACTICE
for Examples 1 and 2 3.
2 –1 –3 –
– –5
– 4
ANSWER –
28 – –4

7. GUIDED PRACTICE
for Examples 1 and 2
4 –1
–3 –5
–2 –2 4. 3 +
ANSWER
3 –3 –

8. GUIDED PRACTICE
for Examples 1 and 2