Question

what is the inverse of the matrix???
[-8 5;
8 -3]

Answer 1

1/-16(8 8/5 3)

Answer 2

i think it might be negate a11b22 and switch b11a22

Answer 3

NOPE this one above is not correct you need 1/determinant

Answer 4

bnut is correct, dont forget to divide by the det of the original matrix.

Answer 5

Yeah...So the determinant is -8(-3)-40=-16
So you have:
\[A^{-1}=\left[\begin{matrix}\frac{3}{16} & \frac{5}{16} \\ \frac{1}{2} & \frac{1}{2}\end{matrix}\right]\]

Answer 6

I thought it in my head but just forgot to type it lol

Answer 7

i always forget which one to negate and which two to flip. you could alway to the adjoint