Question

Last question and then I'm done with my high school years!!! Please help! See picture below!

Answer 1

Important rule to remember in linear algebra:

The matrix is invertible as long as its determinant is not = 0.

do you know how to find det(A)?

Answer 2

No, I do not

Answer 3

for the matrix:
\[A = \left[\begin{matrix}a & b \\ c & d\end{matrix}\right]\]

\[\det(A) = ad - bc\]

Answer 4

and for further reference.

\[A^{-1} = \frac{ 1 }{ \det(A) }\left[\begin{matrix}d & -b \\ -c & a\end{matrix}\right]\]

Answer 5

Oh great, thank you!!

Answer 6

Would it be C then? @Euler271