Question

Determine the value of C21 in the matrix equation BA = C.

Answer 1

what are A and B?

Answer 2

So the first number is what row it's in and the second number is what column it's in. So if this is what C looks like: \[\left[\begin{matrix}c_{11} & c_{12} \\ c_{21} & c_{22}\end{matrix}\right]\]

that shows you where they'll be in the matrix.