Question

Use a matrix to find the solution to the system of equations.

Answer 1

answers:
(-6,8)
(6,8)
(8,-6)
(6,-8)

Answer 2

@touseii45 help?;)

Answer 3

@thomaster help?;D

Answer 4

@Mertsj @jim_thompson5910

Answer 5

which methods are you familiar with?

Row Reduction?

Cramer's Rule?

Matrix Inverses?

Answer 6

Im not familiar with any of these haha sorry. Ive been really sick and they jumped me a class for some reason so i honestly have NO IDEA what should be done in this problem :/

Answer 7

oh so you're in the completely wrong class? that can't be good

Answer 8

you've covered matrices though right?

Answer 9

Yeah :/ And when i ask for help they basically tell me look it up and i ALREADY have a hard time learning math over all and im like 15 assignment late....which i have NEVER been that many before.

Answer 10

yes i have but its only a brief section

Answer 11

well unfortunately matrix math is hard to explain and write out (or draw out)

which is why a lot of people just say "look it up"

to add more problems, there are multiple ways to solve the same problem (ex: you could use Cramer's rule or row reduction)

Answer 12

what kinds of things have you learned so far about them?

Answer 13

just how to put an equation into a matrix form

Answer 14

so matrix multiplication never came up?

Answer 15

nahh not yet i dont think.

Answer 16

ok so that may make the inverse route kinda difficult since you need to know how to multiply matrices

Answer 17

how about determinants?

Answer 18

grrrr >.<

Answer 19

whats that? haha

Answer 20

hmm was afraid of that

Answer 21

let me think on how to approach this

Answer 22

ugh im really sorry :( I'll just guess on this one

Answer 23

no there's a way to use a calc at least so you get the right answer

Answer 24

I just wanted to show you how, but if you don't have the tools needed, then it's very difficult (you have to learn the tools first)

Answer 25

one sec

Answer 26

okay

Answer 27

luckily wolfram alpha is a very handy tool for solving this sort of thing

you just type in the given equations to get this

http://www.wolframalpha.com/input/?i=8x-8y%3D-16%2C6x-9y%3D-108

Answer 28

oh wait, made a typo, let me fix

Answer 29

here's the fix

http://www.wolframalpha.com/input/?i=-8x-8y%3D-16%2C6x-9y%3D-108

Answer 30

and when you get more time, i recommend reading up about matrix multiplication, matrix inverses, matrix determinants, and matrix row reduction

hopefully all that is in your lesson somewhere

Answer 31

thanks a lot :)

Answer 32

np

Answer 33

you put this problem in the form

A v= b
where A is the 2 x 2 matrix
A= -8 -8
6 -9
v is x
y
and b is
-16
-108

Here is how to find the inverse of a 2 x 2
http://www.khanacademy.org/math/algebra/algebra-matrices/inverting_matrices/v/inverse-of-a-2x2-matrix

once you found the inverse of the matrix, you multiply
v = Ai * b

see
http://www.khanacademy.org/math/algebra/algebra-matrices/matrix_multiplication/v/matrix-multiplication--part-1