# math

#### kyla

##### New member
given that A = [ 6 5] [-5 -5] and ? =[ 5 0] [-5 -1], find the following

A. A + B
B. 5A
c. 3A - 2B
d. AB

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#### Subhotosh Khan

##### Super Moderator
Staff member
given that A = [ 6 5] [-5 -5] and ? =[ 5 0] [-5 -1], find the following

A. A + B
B. 5A
c. 3A - 2B
d. AB
What are 'A' & 'B'?

Are those numbers or vectors or animals (like aardvarks, bats, etc.) ?

I believe your post is missing some data.

#### kyla

##### New member
idk I don't know this is the equation

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#### Dr.Peterson

##### Elite Member
given that A = [ 6 5] [-5 -5] and ? =[ 5 0] [-5 -1], find the following

A. A + B
B. 5A
c. 3A - 2B
d. AB
We can guess that the second matrix is supposed to be B; you should point out the typo to your teacher, though.

Now, do you know how to add matrices and multiply by a scalar, and multiply matrices? If not, you'll have to open your textbook! Or at least find a site like this one to teach you: https://www.mathsisfun.com/algebra/matrix-introduction.html

Then give it a try and show us what you get, so we can see if you need help.

#### kyla

##### New member
ok I think I got it,A + B = [11 5], [-10 -6],
5A = [30 25], [-25 -25]
3A - 2B = [ 8 -15] [5 -13]
AB = [5 -5], [0 -5]

#### Dr.Peterson

##### Elite Member
Most of that looks good; just check your signs on a few elements in the last two answers.

ok thank u