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

##### 1 Answer

Mar 10, 2016

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#