Question

Pre-Caluclus Question
http://prntscr.com/127afe

Answer 1

B is what I picked and got it wrong lol

Answer 2

\[x+y+z=9\\2x-3y+4z=7\\x-4y+3z=-2\]
\[\begin{bmatrix}1&1&1\\2&-3&4\\1&-4&3\end{bmatrix}\begin{bmatrix}x\\y\\z\end{bmatrix}=\begin{bmatrix}9\\7\\-2\end{bmatrix}\]

Answer 3

what do i do here?

Answer 4

(I have to teach myself. So thats why i come on here. people like you are fantastic in times like these. and I learn a lot)

Answer 5

R?

Answer 6

\(R\) for row.

so if i do the first row operation
\[\left[\begin{array}{ccc|c}1&1&1&9\\2&-3&4&7\\1&-4&3&-2\end{array}\right]\\\sim\left[\begin{array}{ccc|c}1&1&1&9\\2-2(1)&-3-2(1)&4-2(1)&7-2(9)\\1&-4&3&-2\end{array}\right]R_2→R_2−2R_1\\\sim\left[\begin{array}{ccc|c}1&1&1&9\\0&-5&2&-11\\1&-4&3&-2\end{array}\right]\]

Answer 7

keep performing row operations
until you get
\[\sim\left[\begin{array}{ccc|c}1&0&0&x_1\\0&1&0&y_1\\0&0&1&z_1\end{array}\right]\]

Answer 8

the second row operatio i would make is
\[R_3→R_3−R_1\]

Answer 9

So the first row is R2,R2,,R1
and the 2nd is R3,R3,R1?

Answer 10

?

Answer 11

I cant make out what the row operation is for the 2nd one. is that a 3 beside the R

Answer 12

\[\Large R_3→R_3−R_1\]

Answer 13

\[\large\sim\left[\begin{array}{ccc|c}1&1&1&9\\0&-5&2&-11\\1-(1)&-4-(1)&3-(1)&-2-(9)\end{array}\right] R_3→R_3−R_1\]

Answer 14

Im trying to figure out what you did in the first one

Answer 15

for the first row operation, i just took away (two times) the first row from the second row

Answer 16

okay
starting to get there

Answer 17

On the 3rd row i see what you did in the 2nd column

Answer 18

What did you do at the bottom?

Answer 19

pardon ?

Answer 20

is it A?

Answer 21

after my second row operation, i found that two rows were equal, which makes the system unsolveable

Answer 22

or did i do something wrong

Answer 23

i dont know , i can't see you working,

Answer 24

So if its unsolvable. What do i put as my answere? I only have the A.CD choices.

Answer 25

Oh I got it!!! duh! I had a blockage there for a moment.

Answer 26

you got it?