Question

use the matrix tool to solve the system of equations.
8x+5y=9
-x+y=7

Answer 1

so have you covered "inverse matrices" yet?

Answer 2

what's that.?

Answer 3

http://www.youtube.com/watch?v=PTN8rganLWo

Answer 4

yea I did.

Answer 5

so, what would you get for the determinant for the 2x2 => \(\bf \left[\begin{matrix}
8 & 5 \\
-1 & 1
\end{matrix}\right]
\)

Answer 6

1/(8)(1) 1/(-1)(1) .?

Answer 7

the video covers also how to get determinants :)

Answer 8

1/ ad-bc

Answer 9

well, that'd be the inverse of it, yes

Answer 10

which you'd be needing too

Answer 11

let us first find the determinant only :)

Answer 12

kay. then umm..?

Answer 13

so, what did you get for the determinant of \(\bf \left[\begin{matrix}
8 & 5 \\
-1 & 1
\end{matrix}\right]\)

Answer 14

9&7.?

Answer 15

the video is worth the while, it covers using the inverse determinant to solve the system, and matrix multiplication too :)

Answer 16

okay. then.

Answer 17

but when does he talk about the determinant.?

Answer 18

7-4=3.?