Question

Medal for Matrix help.

How would I solve for x?
[-8 -14 -2x] = [2 -74 -6]

Answer 1

what row by column matrix is this?

Answer 2

1 x 3 for both

Answer 3

so is A - [-8 -14 2x] and B =[2 -74 -6]?

Answer 4

it's like find an x that will make both matrices equal...

Answer 5

Yeah, that's the issue. I have no idea how to find x in this situation. It's been a while since I've done a problem like this.

Answer 6

oh how about if we have something like this

-2x=-6 then we just solve for x. Because what I am assuming is that the last entry in A and B are supposed to be equal.

Answer 7

I have done these, but with 2x2 or above

Answer 8

I could give you the possible answers if that would help?

Answer 9

a. x = -5.7
b. x = -17.7
c. x = 7
d. x = 6

Answer 10

yes please

Answer 11

what the O_O!

Answer 12

Yeah...my reaction exactly.

Answer 13

this is so weird.. I'm calling wolfram lol

Answer 14

lol okay. That's a good idea.
This was the original problem...

\[[-8 -14-2x] - ([-19 +17 -1] + [14 +13 -2]) = [-3 -44 -9]\]

Answer 15

T_T wait a sec.. I might have ... did you do the operation in paraenthesis first?

Answer 16

Oops! Ignore the plus signs. I dunno why I put them inside the matrices.
and yes I did. Was I not supposed to?

Answer 17

-.- ok hold on I think I might have see what is going.. yes you should do the ones in paraenthesis first ..

Answer 18

Question: how A = B??

Answer 19

that's what I was thinking too.

Answer 20

what makes A=B ? but when I was to do the problem.. if I let x = 3 that last part will be equal but the first 2 entries aren't equal

Answer 21

if A = B ,then -8 =2??
-14 =-74
-2x = -6 but how??

Answer 22

something is wrong with the arithmetic.

Answer 23

let's do it over... and no shortcut cheats.. now this is the original problem right?
\[[-8 -14-2x] - ([-19 +17 -1] + [14 +13 -2]) = [-3 -44 -9]\]

Answer 24

That wouldn't surprise me. I've been doing math since about 10 am.

and yes it is.

Answer 25

\[[-8, -14,-2x] - ([-19 , 17 , -1] + [14, 13 ,-2]) = [-3, -44, -9]\]

Answer 26

let me put on my cglasses

Answer 27

now let's do the ones in the () with adding the matrices.

Answer 28

\[- ([-19 , 17 , -1] + [14, 13 ,-2]) \]

Answer 29

\[- ([-19+14 , 17+13 , -1-2] )\]\[-[-5,30,-3] \rightarrow [5,-30,3]\]

Answer 30

\[[-8 -14-2x] - [5, -30, 3] \rightarrow [-8-5-14-(-30),-2x-3]\] are you sure it's not
[8, -14, 2x] ?

Answer 31

\[[8 -14-2x] - [5, -30, 3] \rightarrow [8-5-14-(-30),-2x-3] \rightarrow [3, 14+30,-2x-3] \rightarrow [3, 44, -2x-3\]
\[ \rightarrow [3, 14+30,-2x-3] \rightarrow [3, 44, -2x-3]\]

Answer 32

yay I think I got what x is !

Answer 33

on the last entry we have to solve for x so now we have

\[ [3, 44, -2x-3] = [3, 44, 9]\]

Answer 34

Really?
(sorry, I'm doing this an something else at the same time)

Answer 35

wait a sec... I think there are typos

Answer 36

I think.. let me do this on paper.. there is a typo somewhere on your end or something.

Answer 37

Okay.

Answer 38

-_- I got x = 3. who are these people giving these choices anyway?

Answer 39

\[[-8, -14, 2x] +[ 5 -30 ,3] = [-8+5, -14-30, 2x+3] = [-3, -44, 2x+3]\]

Answer 40

It's just random questions I'm given for practice.
At the moment, I am unable to view the question, but as soon as I can, I'll let you know if there were any typos in my copy.

Answer 41

\[[-3, -44, 2x+3] = [-3, -44, -9]\]

there could be typos on my end but I got it... ok THIS TIME I AM CERTAIN I GOT IT!

Answer 42

we just have to focus on the last equation because our first two entries are equal so we now solve for x for that last entry
2x+3=-9

2x =-9-3
2x=-12
x =- 6

there's a typo in your multiple choice

Answer 43

yup x = -6 \[[-3, -44, 2(-6)+3] = [-3, -44, -12+3] = [-3, -44, -9]\]

Answer 44

yay finally it's over. can I get a medal for this 1 x 3 horror festival? I'm not use to adding and solving like that XD

Answer 45

-2x+3 = -9
doh I dropped a sign. It's D
-2x = -9-3
-2x=-12
x=6

Answer 46

You're awesome! :D
Hopefully I'll never get another question like this again, but thank you so much for all your help.

Answer 47

that question sucked... I was never given like this and I'm used to adding vertically!

Answer 48

Honestly, I've never had one like this either. The moment I looked at it, my brain went blank.

Answer 49

it was tedious. doable but tedious... I think the latex threw me off too. That's why I got so many answers and what not.

Answer 50

Cleaned up version

\[[-8 -14-2x] - ([-19 +17 -1] + [14 +13 -2]) = [-3 -44 -9]\]
\[\[[-8 -14-2x] - ([-19+14 , 17+13 , -1-2] ) = [-3 -44 -9]\]
\[\[[-8 -14-2x] - ([-5, 30 , -3] ) = [-3 -44 -9]\]
\[\[[-8 -14-2x] +([5, -30 , 3] ) = [-3 -44 -9]\]
\[\[[-8+5, -14-30,-2x+3] ) = [-3 -44 -9]\]
\[\[[-3, -44,-2x+3] ) = [-3 -44 -9]\]

\[-2x+3=-9 \]
\[-2x+3-3=-9-3 \]
\[-2x=-12 \]
\[\frac{-2x}{-2}=\frac{-12}{-2}\]
\[x=6\]

\[\[[-3, -44,-2(6)+3] ) = [-3 -44 -9]\]
\[\[[-3, -44,-12+3] ) = [-3 -44 -9]\]
\[\[[-3, -44,-9] ) = [-3 -44 -9]\]