Question

What is the solution of the matrix equation?
[9 4] [-9 -6]
X=
[2 1] [-1 -8]

Answer 1

if the left matrix is invertible ....

Answer 2

otherwise you can create a system of equation and solve the usual way

Answer 3

since the determinant is 1, the inverse is just a matter of swapping corners and negating the others .... visually that is.

Answer 4

@amistre64 so i just swap the numbers?

Answer 5

there is a visual memorization for 2x2 matrix inverting. swap out topleft and bottomright corners

negate the other 2

divide all elements by the determinant

Answer 6

the proper algorithm for an inverse has to do with submatrix determinants, transposing, and such ...