FUNDAMENTALS OF BUSINESS MATHEMATICS AND STATISTICS I 2.65(2) Find X & Y
Where 3X + 2Y = −^3 1 2^7X – Y= 81 − 96
Ans. X^11 Y^05
3 4 5 5(^) = − (^) =
(^) − −^
(3) Find ‘X’
Where AX = B
A = 1 29 4
B =13 52^312
Ans. x 1 4
1 4 =
2.8.2. DETERMINANTS
The determinant of a square matrix is a number that associated with the square matrix. This number may be
postive, negative or zero.
The determinant of the matrix A is denoted by det A or |A| or ∆
For 1 x 1 matrix A = [3]
|A|= 3
For matrix A = [–3]
|A|= – 3
For 2 x 2 matrix A = a bc d
|A|= a bc d =ad bc−
For 3 x 3 matrix A =
a b c
d e f
g h i
|A| =
a b c
d e f
g h i
a e f b d f c d e
h i g i g h= − +
= a (ei – hf) –b (di – gf) + c(dh – ge)