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do you have to do it with matrices?

addition *

ill show you what im talking about

not really getting your point
inverse of 2x2 matrix can be computed like this
|dw:1433291928663:dw|

$$\Large {A}\mathbf{ x} = \mathbf{b}
\\ \Large \mathbf{ x} = A^{-1} \mathbf{b}$$

I know ...... :(((((

try to find the determinant first

ok the determinant is computed like this
|dw:1433292400098:dw|

ok

you multiply ad and bc
and then subtract

ok
thats all ?

do the same with your matrix

no not finished that's only how to do determinant

ok im writing this down

cross multiply ?

yeah seems like cross multiply
then take the difference

so for me it would me 9*1 &4*2 for A and for X it would be -9*-8 and -6 *-1 right?

or did you mean multiply A with X ???

so here
\[A=\begin{bmatrix}9&4\\ 2&1\end{bmatrix}\]
\[\det(A)=9(1)-2(4)=9-8=1\]

oh no what are you taling about? are you following what i'm saying haha

yeah

9*1 i did that 2*4 i did that too

we are looking for X
and i used what perl did
X=Ainverse times B

i know what i did wrong i forgot to subtract ..

no seems you missed the whole poiint from what i understand from your last reply

no .. i didn't you said cross multiply then subtract right ???

that's only for determinant

i did that for you already see my replay above

ok so what do have to do next then ?

find x ?

|dw:1433293368759:dw|

yup

so we do 1/det A
so 1/1 =1
here we didn't need to worrt about it since it is just 1

ok

next step is to do a switch|dw:1433293517899:dw|

you take A and switch a and d
b and no switch you just change the sign

ok i get that but where do the negatives come from

it is a rule you need to read about it on your notes

what kind of class are taking

algebra 2

hmm really?
i don't really know how much you know about matrices

okay , i will

i will do your problem now, but next problem you need to try your hardest :)

okay

let me do it on paper ans take a picture

ok

almost hehe

kay

before the last line i preformed matrix multiplication

is it readable ?

yeah it is . -5 ,26 -9 and -60 correct right

there is no -9

oh ,

that's just brackets

that should match C

oh , my bad it looked like a negative for a second but yes it is C

okay

hope that helps

it does ,,,,, THANKS ..

my pleasure