Open study

is now brainly

With Brainly you can:

  • Get homework help from millions of students and moderators
  • Learn how to solve problems with step-by-step explanations
  • Share your knowledge and earn points by helping other students
  • Learn anywhere, anytime with the Brainly app!

A community for students.

Check my answer Solve with matrices. 5x -3y = 18 and 2x + 7y = -1 I got .... x=31/18 y=-3/5 Am I right?

Mathematics
I got my questions answered at brainly.com in under 10 minutes. Go to brainly.com now for free help!
At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.

Get this expert

answer on brainly

SEE EXPERT ANSWER

Get your free account and access expert answers to this and thousands of other questions

no...but remember you can check for yourself, plug in those values
.... that was my line panlac lol
my bad... I can delete it

Not the answer you are looking for?

Search for more explanations.

Ask your own question

Other answers:

no need to delete :)
Oh okay, well I did & it wasn't.. Crud. Well I am confused on part of it, so when I have to do one row of the matrices that is 5 -13 18 to get it to 1 0 c1 How do I do that?
is this cramer rule? or row operations?
I think row of operations is the way to go.
Uhh. I don't know.. But I have to get the row to 1 0 c1, like 5 has to change to 1 and -13 has to change to 0 somehow.
yeah you have to divide the whole row by 5 then
hey cutie,have u been taught matrix inversion?which makes the solution much simpler.....
@RyanL. Well that would give me 1 -13/5 18/5. How would I get -13/5 to zero with out changing the 1? @hartnn Maybe, math isn't my strong point to I have no idea the fancy names... Sorry.
Well when we row reduce we want every number bellow that 1 to be a zero
|dw:1344704018436:dw| well you need to subtract the second row by the first row but before that you need to multiply the first row by 2
Why would you multiply the first row by two?
Oh wait, nevermind! I gotcha now!
|dw:1344704116600:dw|
|dw:1344704166215:dw|
then divide the second row by 8.20 and then subtract the the first row by the second.
so the bottom row would be 0 1 -1 ? And would that give you.. 1 2/5 13/5 ?
|dw:1344704298500:dw| I like to make them 1s so if I need to divide to multiply it it's going to be easier to do it later.
Well no I see that I want to make the first row second column zero right. I'm talking about this number|dw:1344704459156:dw|
so I then multiply the second row by\[\frac{3}{5}\]and then add it to the first row
|dw:1344704521394:dw|
|dw:1344704554208:dw|
|dw:1344704592083:dw|
multiply the second row by \[\frac{5}{3}\]now to get them back to 1
|dw:1344704647344:dw|
tough to teach row operations online...there are a lot of steps use matrix algebra \[Ax = b\] \[x=A^{-1}b\] where A is coefficient matrix and b is right side constants \[\left(\begin{matrix}5 & -3 \\ 2 & 7\end{matrix}\right)\left(\begin{matrix}x \\ y\end{matrix}\right)= \left(\begin{matrix}18 \\ -1\end{matrix}\right)\] \[\left(\begin{matrix}x \\ y\end{matrix}\right)= \left(\begin{matrix}5 & -3 \\ 2 & 7\end{matrix}\right)^{-1}\left(\begin{matrix}18 \\ -1\end{matrix}\right)\] det(A) = 5*7 - 2*-3 = 41 \[\left(\begin{matrix}5 & -3 \\ 2 & 7\end{matrix}\right)^{-1} = \left(\begin{matrix}7/41 & 3/41\\ -2/41 & 5/41\end{matrix}\right)\] \[\rightarrow \left(\begin{matrix}x \\ y\end{matrix}\right) = \left(\begin{matrix}3 \\ -1\end{matrix}\right)\]
Yeah but row operations is essential to everything that you will learn ahead so you need to be able to do them at ease. After a while it takes seconds.
And I made a mistake I left out a negative sign here|dw:1344704797494:dw|
Thanks @dumbcow It's always good to show that there is more than one way to solve a problem.
Oh, so when you multiply and add and what not, does it not apply to the first number in the row?
Well I think you mean when we add the second row to the first. The thing is that the first number is a zero so if you multiply it a zero by a number or divide it by another number it will remain zero so when we add it to the first row we will be adding or subtracting a zero.
And when you add or subtract a zero from a number it stays the same.
Okay, I gotcha. Thanks for the explanation. :) It really helped!
No problem sorry for the messy work hope you could understand it .
I did :)

Not the answer you are looking for?

Search for more explanations.

Ask your own question