Question

Can someone look at this and tell me what I did wrong to get this answer??? Will medal!

Answer 1

This took me so long to do I'm so upset... I was so proud of myself until I got that answer :(

Answer 2

why does the formula require the inverse? Wait I see what the problem is. You don't have to include x y z you just include the numbers that are attached to the x y z in the set of linear equation s

Answer 3

um, explain?

Answer 4

someone told me that the formula was A^-1*B...

Answer 5

and when I looked it up that was correct, using the inverse

Answer 6

inverses are such a pain, when they get big its sometimes more efficient to use augmented form.

Answer 7

I think something happened to your calculations.. your x is huge

Answer 8

that's what I was trying to say... put it in an augmented matrix format and use row operations...

Answer 9

I don't remember learning that I don't understand!

Answer 10

rref{
{1,1,1,4},
{4,5,0,3},
{0,1,-3,-10}
}

http://www.wolframalpha.com/input/?i=rref%7B+%7B1%2C1%2C1%2C4%7D%2C+%7B4%2C5%2C0%2C3%7D%2C+%7B0%2C1%2C-3%2C-10%7D+%7D

Answer 11

less room for error in my opinion

Answer 12

do you see the original system of equations? YOu just put the numbers from the systems of equations like this

1 1 1 l 4
4 5 0 l 3
0 1 -3 l -10

and use row operations... you don't have a 0 in the main diagonal so row swapping isn't required.

Answer 13

just tell me what I did wrong so I can fix it and move on! I've been working on this problem for HOURS

Answer 14

lol math making people crazy when ever they can't find the answer ;D

Answer 15

I don't understand :'(

Answer 16

nothing nothing they are going help :D

Answer 17

your inverse has one bad spot ... row1 col3: should be -5

Answer 18

I used a calculator to find the inverse.... it shouldn't be wrong..... but I'll double check

Answer 19

I would've used augmented version and use row operations..

Answer 20

it prolly had a negative, and you might have missed it ... but thats the trouble spot

Answer 21

oh... you're right @amistre64 I wrote it wrong...

Answer 22

I've made plenty of mistakes on my exams xD! It's not a problem. xD

Answer 23

thank you so much... @amistre64 I'll calculate it now and look at my answer to see if its correct this time

Answer 24

-50 instead of +50, so your 100 off on the first row :)

100-98 = 2

Answer 25

good effort

Answer 26

haha thanks I'm not sure who to give the medal to... :P

Answer 27

@amistre64 can you give @UsukiDoll a medal for me since I medaled you?

Answer 28

interesting.. so there is more than one method to solve this... my professor didn't even teach the inverse version... just told me to put it in augmented matrix form and row operations solve away until I have reduce row echelon form. So the final matrix wouldv'e looked like this

1 0 0 l 2
0 1 0 l-1
0 0 1 l 3

for x =2, y = -1, z=3

Answer 29

Much better :D

Answer 30

yay :)