Page 13 - Focus SPM KSSM 2021 Tingkatan 5 - Maths DLP

Mathematics Form 5 Chapter 2 Matrices

9
(c) [3 –4] 3 4 Solution 1 3
12
= [(3 × 9) + (–4 × 12)] [4x 9] 3 2 –x 4 = [x 2y]
= [27 – 48] [4x + 18 12x + (–9x)] = [x 2y]
= [–21] Compare the corresponding elements:

4x + 18 = x 12x − 9x = 2y
18 3x = −18 3x = 2y
x = −6 2y = –18
8
It is given that P = 3 3 9 4 and Q = 3 5 1 –3 4 . Find y = –9 Chapter 2
–2 –4
(a) PQ Try Questions 11 – 14 in Try This! 2.2
(b) QP
Chapter 2
(c) Q Example of HOTS
2
HOTS Question
Solution Madam Dahniah’s catering company receives orders
(a) PQ = 3 3 9 43 5 8 4 from two customers, A and B. The table below shows
the number of orders of both customers.
–2 –4 1 –3
= 3 15 + 9 24 + (–27) 4 Customer A Food Drink
–16 + 12
–10 + (–4)
45
60
= 3 24 –3 4 Customer B 82 50
–14 –4
It is given that the preparation costs of the food and
drink are RM30 and RM8 for each order respectively.
(b) QP = 3 5 8 43 3 9 4 Calculate the total preparation cost for both
1 –3 –2 –4
customers’ orders.
= 3 15 + (–16) 45 + (–32) 4 Solution: 1800 + 360
9 + 12
3 + 6
60 45 30
=
8
2460 + 400
= 3 –1 13 4 3 82 50 43 4 3 3 2160 4 4
9 21
=
2860
(c) Q = QQ Total preparation cost = 2160 + 2860
2
= RM5020
= 3 5 8 43 5 8 4 Try this HOTS Question
1 –3 1 –3
= 3 25 + 8 40 + (–24) 4 Roshan’s shop sells black cartridge and colour
5 + (–3)
8 + 9
cartridge for printer. The table below shows the
= 3 33 16 4 sales of the cartridges for three months.
2 17
Colour cartridge
Black cartridge
January 10 6
REMEMBER! February 12 4
March 8 5
(a) When multiplying matrices P and Q, PQ is not
necessarily same as QP. It is given that the profits earned from selling each
5 2 8 2 black cartridge and colour cartridge are RM10 and
(b) Q ≠ 3 2 24 RM8 respectively. Calculate the total profits, in
2
1 (–3)
RM, earned in January, February and March in the
form of matrix.
148
3 4
19 Answer: 152
Solve the equation [4x 9] 3 1 3 4 = [x 2y]. 120
2 –x
25

02 Focus Math F5_E2021.indd 25 18/02/2021 2:32 PM