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

Mar 10, 2016

7

#### Explanation:

For the general 2X2 matrix : $\left(\begin{matrix}a & b \\ c & d\end{matrix}\right)$

The determinant is : ad - bc written$| \left(a , b\right) , \left(c , d\right) | = a d - b c$

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

hence determinant $= \left(2 \times 3\right) - \left(1 \times - 1\right) = 6 + 1 = 7$