Help With adding Matrices??

Question

I dont understand how you do this.

if:


A= 20 -10
......12 19


B= 15 14
......-10 6


C= -5 7

Find each sum, difference, or product. If the Sum does not exist, write "impossible"

The it says to do the following problems with the Matrices:

1. A + C

2. B - A

3. 2A

4. -4C



This is from a "Glencoe Mathematics Algebra 1" Text Book.

Answer 1

have u been taught this? i'm sure if u were asked to do these questions you would have been properly taught it. but i could be wrong...

1) impossible, u can only add or subtract matrices that have the same dimentions ie: same number of columns and rows

2)possible, simply subtract each term of A from B in their correct positions

3) possible, times every term in the matrix by 2

4) possible, times every term in the matrix by -4

you can try the working out

Answer 2

OK - to add matrices, you simply add the corresponding entries. So to add A and B you would add 20 and 15 to get 35 - that would be the upper left entry. Do that with the other three entries. You can only do this with matrices of exactly the same size - so you can't add A and C. To calculate B - A, you're really just adding a negative ... so the first entry would be 15 - 20 = -5.

To do 2A means to multiply each entry in A times two, so the upper left entry would be 15(2) = 30.

Answer 3

element by employing element. Matrices might desire to be the comparable length (m x n) [C]=[A]+[B] Such that Cmn=Amn+Bmn as an occasion If [A]= 3 a million 0 4 2 -a million And [B]= 2 5 a million a million 0 a million Then [C]=[A]+[B]= 5 6 a million 5 2 0

Answer 4

You can only add two matrices together if they have the same exact dimensions. So #1 is impossible, but #2 you could do. Just add or sutract cell by cell. #3 and #4 deal with multiplying an entire matrix by a single number, which you can always do. Multiplying two matricies together though is a different story.