Question

How do you find the determinant of `((2, 1), (-1, 3))`?

Answer 1

7

Explanation:

For the general 2X2 matrix : `((a,b),(c,d))`

The determinant is : ad - bc written`| (a,b),(c,d)| = ad - bc`

For the matrix here: a = 2 , b = 1 , c =-1 and d = 3

hence determinant `= (2xx3) - (1xx-1) = 6 + 1 = 7`