## kenneyfamily 3 years ago 4x - y = 1 x + 2y = 7 how could i solve this using an inverse matrix?

1. tkhunny

1) Use the coefficients to form a 2x2 matrix. 2) Augment this matric by I2 3) Perform row operations to find the inverse of the original matrix. Are we ringing bells?

2. kenneyfamily

No..

3. kenneyfamily

would you write the matrix as 4 -1 1 2

4. tkhunny

That is part #1. Very good. Next...

5. kenneyfamily

what do you mean by augment it by I2?

6. tkhunny

$\left[\begin{matrix}4 & -1 & 1 & 0\\ 1 & 2 & 0 & 1\end{matrix}\right]$

7. kenneyfamily

why did you do that? sorry i'm confused

8. tkhunny

Well, this is one very useful way to find an Inverse Matrix. You've never seen it, before?

9. kenneyfamily

I may have but I forgot how to do it

10. tkhunny

How about "Elementary Row Operations"? Any of those floating around in your bag of tricks?

11. kenneyfamily

I wish I could say yes but no. I'm retaking a pre-calc course because i failed it the first time

12. tkhunny

Well, you're going to have to get a few things up to speed. Finding an inverse matrix is an important skill. You'll have to start somewhere. Try this: http://www.youtube.com/watch?v=RsTdy2r9DHk

13. kenneyfamily

ok thanks!!