Question

Pre-Calculus question

Solve the matrix equation for X.

Let A =
and B =
4X + A = B

Answer 1

The choices are

Answer 2

\[4X + A = B\\X=\frac{B-A}4\]

\[X=\frac{\begin{bmatrix}3&-3\\-4&0\\8&-2\end{bmatrix}-\begin{bmatrix}8&0\\0&-6\\3&-2\end{bmatrix}}4\\
\qquad=\frac{\begin{bmatrix}3-8&-3-0\\-4-0&0-(-6)\\8-3&-2-(-2)\end{bmatrix}}4\]

Answer 3

What do i do after that?

Answer 4

Sorry im not good at the matrix stuff lol

Answer 5

simplify each element in the matrix, (the first element 3-8=-5 ,, etc )

then divide each element by 4

Answer 6

its not hard,

Answer 7

im not sure where you are having difficulty ..

Answer 8

one sec
tell me if im right or not

Answer 9

sure,

Answer 10

wait. if i divide by 4 i wont get the right answere

Answer 11

what do you have (before dividing by four)

Answer 12

subtract?

Answer 13

yes

Answer 14

so would it be (from left to right)
-5,-3
-4,-6
5,0

Answer 15

So its D?

Answer 16

almost, 0-(-6) should be 6, not -6

Answer 17

oops. i had it right on my paper.

Answer 18

I typed it wrong

Answer 19

ah ok,

so now

-5, -3
-4, -6 /4
5, 0


=
-5/4, -3/4
-4/4, -6/4
5/4, 0/4

= ... (not D)

Answer 20

hmm.. :/ it cant be B. I had that and it said I was wrong

Answer 21

So i figured when it got divided the signs would change maybe.

Answer 22

Whops.

i think i got the matrices in the wrong order

Answer 23

let me do this. maybe it will help you

Answer 24

***
\[X=\frac{B-A}4=\frac{\begin{bmatrix}8&0\\0&-6\\3&-2\end{bmatrix}-\begin{bmatrix}3&-3\\-4&0\\8&-2\end{bmatrix}}4\]

Answer 25

would the first one be 8-3?

Answer 26

yeah, go on ...

Answer 27

5,3
4,-6,
-5,0

Answer 28

and when divided by 4

Answer 29

thats good, what do you get after dividing ?