Question

Matrices question

Answer 1

hi, where are you stuck at, or do you have no idea where to start?

Answer 2

Well, I have no idea, My teacher hasn't shown us what do with this type of problem

Answer 3

We have used cramer's rule before but not like this

Answer 4

ok ^_^ no problem
can you find the determinant? if not I can show ya

Answer 5

@DarkBlueChocobo ?

Answer 6

This problem only takes one step to solve, I just worked it out.
all we need to do is take the determinant, and you'll see what the answer is

Answer 7

I know how to work in like a normal matrix but I have not done this before o_o where do you start?

Answer 8

^_^
soo, inorder to solve this matrix, we need to get all the non-variable terms to one side. see how the second equatoin is already in this form? we need to get the top equation so the x and y terms are the only thing on that side. this is the first thing when working with a matrix, we want to make it 'square'

Answer 9

\[4x+y=6? \] and then the other one is alright as is because all the variables are on the same side

Answer 10

yep with a negative ^_^
4x + y = -6

now we have
4x + y = -6
8x+2y = 9

so can you put this into matrix form?

Answer 11

I'll do the first one as a hint..

[ 4 1 ]
[ ? ? ]

Answer 12

8 2?

Answer 13

and then -6 9?

Answer 14

correct, so here is what our square matrix for cramer's rule looks like. its only the coefficients of the x and y terms.
[ 4 1 ]
[ 8 2 ]

the -6 and 9 are used later in the process, but not yet.

so we need to take the determinant of our matrix.
remember it's the down hill - the up hill of the matrix, can you do this? or I can show you

Answer 15

it would be 8-8=0

Answer 16

would it be that?

Answer 17

yep ^_^

Answer 18

o:

Answer 19

so the determinant equals zero, or D=0
cramer's rule only works when \[D \neq 0\]

Answer 20

so no solution then

Answer 21

so, that is why your professor gave you this question w/o teaching you how to do cramers rule.
he gave it to you to understand D can = 0 to use cramers rule.

Answer 22

no solution would have been my first guess. but D = 0 just means you have to solve this system with a method you have previously learned. either elimination or substitution.

Answer 23

o goodness ._.

Answer 24

This seriously is just blegh ._. So much solving just to get to a point where you have to do more solving

Answer 25

haha, i thought you'd like that answer

Answer 26

lol,
fortunatly cramer's rule is that last of the methods to teach you how to solve systems of equations.

Answer 27

lol well the points given for the answer filled in don't work out so

Answer 28

no solutions it is

Answer 29

^_^
see, you are smart and can solve quickly!
no solution is correct

Answer 30

Can you help me out with 2 more like this that i am assuming you have to do fully because no solution is no option lol

Answer 31

I believe I can figure it it out mostly since you explained it to me

Answer 32

ya, put them up and message me or what ever and I can just check ur work

Answer 33

\[6x+y=2\]

\[-3x+2y=1\]

Answer 34

6 1 and -3 2 so 6*2 - 1*-3 12+3

Answer 35

so 15?

Answer 36

sorry, helping other people at the same time.
yep 15 is right, so D=15
can you find the determinant for D_x?

Answer 37

How do you find that?

Answer 38

so we had this one, right:


now if we are solving for D_x, or the determinant of X, we replace the x column with the column made from the = side, so it looks like this: