Question

Given A= [4, 9, -2, -3, 5, 7] and C= [2, -1, -3, 1, 4, -2], and A+B=C, what is B?

a. B=[6, 8, -5, -2, 9, 5]
b. B=[2, 10, 1, -4, 1, 9]
c. B=[-2, -10, -1, 4, -1, -9]
d. B=[-6, -8, 5, 2, -9, -5]

Answer 1

2. IF A=[3, -2, 1, 4] and B=[0. -1, 3, 2], what is AB?
a. [0, 2, 3, 8]
b. [3, -3, 4,6]
c. [-1, -4, 11, 2]
d. [-6, -7, 12, 7]

Answer 2

3. given a matrix A=[2, 3, -5, -7] what is A^-1?
a. no inverse
b.[-7, -5, 3, 2]
c. [-7, -3, 5, 2]
d. [7, 3, -5, -2]

Answer 3

For the first one, B = C - A; so, just subtract the components of A from C.

Answer 4

so it would be B?

Answer 5

I don't think so. From the first component of C and A, we get -2.

Answer 6

oh it's negative, whoops xD

number 2?

Answer 7

Number 2 seems odd to me because in order to multiply two matrices, the columns of the first matrix must be equal to the rows of the second. Moreover, if we are calculating the product of two vectors, their dot product will be a number.

Answer 8

The only suggestion I could make would be A.

Answer 9

idk why i thought it was C ._.

number 3?

Answer 10

If you don't mind me asking, what course is this for?

Answer 11

Algebra 2.

Answer 12

For number 3, there is no inverse since A is not n x n

Answer 13

YES I GOT THAT RIGHT. Thank you :D

would you mind helping with others?

Answer 14

Sure. I must go soon, so I will do as many as I can.

Answer 15

alright.

\[\left\{ \frac{ -32x-15y+2z=1001 }{ 73x-3y+811z=-29 } \right\}\] there's 3 rows. the 3rd row is -51x+32y-513z=416

Answer 16

Is this a system of linear equations?

Answer 17

i believe so..

Answer 18

OK. So I find it easiest to use Gauss-Jordan Elimination to reduce the system to reduced row echelon form. Do you know how to do this?

Answer 19

These numbers are unnecessarily large.

Answer 20

I don't remember xD i took this 3 months ago.. they are i agree.

Answer 21

Another question, are you sure the problem was written down correctly?

Answer 22

Yes. There are 3 rows but the equation thingy only let me write 2

Answer 23

Ok. Well, to go through the process of this particular problem would be long and painful because of the numbers involved. The solution is here, http://www.wolframalpha.com/input/?i=-51x%2B32y-513z%3D416+%3B+%E2%88%9232x%E2%88%9215y%2B2z%3D1001%3B+73x%E2%88%923y%2B811z%3D%E2%88%9229 .

Answer 24

Check out this page for how to approach these problems. I must go now. Good luck in your studies. http://www.purplemath.com/modules/systlin6.htm

Answer 25

Thank you.