4.3 Addition and Subtraction of Matrices (Sample Questions)


Example 1:
Find the addition of the following matrices.
(a)(18  7)+(3       6)(b) (13071)+(1356)

Solution:
(a)(18  7)+(3      6)=(18+3  7+6)=(21  1)(b)(13071)+(1356)=(13+(1)0+37+51+6)=(143125)



Example 2:

Find the subtraction of the following matrices.
(a)(96)(72)(b)(3405)(7361)

Solution:
(a)(96)(72)=(976(2))=(28)(b)(3405)(7361)=(3(7)4(3)0(6)51)=(3+74+30+651)=(10164)


Example 3:

Given that (pq)+(5p9)=(123q+1)  , find the values of p and q.

Solution:

(pq)+(5p9)=(123q+1)(p+5pq+9)=(123q+1)
 
p + 5p = 12
6p = 12
p = 2

q
+ 9 = 3q + 1
q – 3q = 1 – 9
2q = 8
q = 4



Example 4:
Find the values of m and n in the following matrix equation.
(76n1)(1m42)=(512611)

Solution:
(76n1)(1m42)=(512611)

6 – m = 12
 –m = 6
 m = –6
n – (–4) = 6
n + 4 = 6
n = 2