Question

suppose A is a (3x1) nxm matrix such that A=
(-4)
(0)
(0)
=
(3x1) matrix:
(36)
(12)
(-4)

what is the first column of A?

Answer 1

your question isnt really clear, perhaps you could use the LaTex equation writer in a comment to write the matrices out properly? then i can help.

Answer 2

suppose that A is an nxm matrix such that A= \[\left[\begin{matrix}-4 \\ 0\\0\end{matrix}\right]\] = \[\left[\begin{matrix}36 \\ 12 \\-4\end{matrix}\right]\]
what is the first column of A?

Answer 3

im sorry, i cant see how that works, how can A be both of those things?

Answer 4

here's a screenshot of the problem to make it more clear

Answer 5

aaah i understand now, A is multiplied by the first matrix to get the second

Answer 6

let\[A= \left( \begin{array}{ccc} a & b & c \\ d & e & f \\ g & h & i \end{array} \right)\]
now do you know how matrix multiplication works?

Answer 7

matrices are only compatible for multiplication if this is true:
if matrix A is n x m and matrix B is p x q , then m = p

also the product of A and B will be of order n x q

therefore we can deduce A must be 3 x 3

Answer 8

ok, thank you