2.64 I FUNDAMENTALS OF BUSINESS MATHEMATICS AND STATISTICS
Algebra
Solution:
3x + y =
2 7
8 9
(i)
2x – y =
3 3
12 11
(ii)
Adding (i) & (ii)
5x =
5 10
20 20
x =
1 5 10
5 20 20
1 2
4 4
=
Put x in (i)
3 1 2 y 2 7
4 4 8 9
+ =
y 2 7^36
8 9 12 12
= −
y^11
4 3
=−
− −
Example 110: Find A^2 + 3A – 2I
Where A = 5 71 3
Solution: A^2 + 3A – 2I
1 3 1 3 3 1 3 2 1 0
5 7 5 7 5 7 0 1
= + −
16 24 3 9 2 1 0
40 64 15 21 0 1
= + −
17 33
55 83
=
SELF EXAMINATION QUESTIONS
(1) Find a, b, c & d
Where
2a b c d 12 2
3a b 2c 3d 13 9
+ − =
− +
(Ans. a = 5 b = 2 c = 3 d = 1)