Question

What is the inverse of the
21 39
matrix
?
49 91​

Answer 1

Step-by-step explanation:

The inverse of A is A-1 only when A × A-1 = A-1 × A = I.

To find the inverse of a 2x2 matrix: swap the positions of a and d, put negatives in front of b and c, and divide everything by the determinant (ad-bc).

Sometimes there is no inverse at all.