Question

solution of system -10 + 6x + 7y = 0 and -x + 2 = y. (solve with matrices). i got x = 4 and y = -2, is that correct?

Answer 1

nope, that is not what I got, how did you set up your matrices?

Answer 2

@Jim766 my friend helped me do it so i have no idea. he just gave me the answer he got. i tried to find how to set up the matrices and it totally lost me. how did you find it?

Answer 3

to set up the matrices you need the x's and y's on one side and the plain numbers on the other

-10 + 6x + 7y = 0
+10 +10
6x + 7y = 10

do you see what I did?

Answer 4

okay that makes sense, but how do you do it with -x + 2 = y, because the variables are on both sides of the equatio

Answer 5

-x +2 = y
-2 -2
-x = y -2
-y -y
-x - y = -2

Answer 6

I gotta tell you that I screwed up when I did it, your answer was correct, do you still want to see how to do it?

Answer 7

i think i get it now. my matrix will be [6 7; -1 1] x [x; y] = [10; -2], right?

Answer 8

i had no idea how to do the matrices in the equation thing lol

Answer 9

right
are you good from there?

Answer 10

i'm still not entirely sure how to solve for x and y with a matrix, even though the answer my friend found was right.

Answer 11

are you using a graphing calculator?

Answer 12

i could if i need to. would it be easier than solving it on paper?

Answer 13

yeah, way easier.... what kind do you have?

Answer 14

ti84 plus

Answer 15

do you know how to enter in a matrix?

Answer 16

get your calculator

Answer 17

i'm trying to figure out why it wont let me put a negative number in the matrix

Answer 18

got it.

Answer 19

it will .... start from the beginning

here are the equations
6x + 7y = 10
-1x -1y = -2

here is my one matrix

6 7 10
-1 -1 -2

see how I got that?

Answer 20

yep

Answer 21

push 2nd matrix and slide over to edit make the matrix 2X3

Answer 22

i have all the values in, now what?

Answer 23

now save it by pressing 2nd quit

Answer 24

now press 2nd matrix and slide to the middle (math)

Answer 25

go up to B: rref( press enter

press2nd matrix again and enter

Answer 26

should look like this

rref( [A] press enter

Answer 27

1 0 4
0 1 -2

Answer 28

the last 2 values are my answers. whaaaaaaaat it's like witchcraft

Answer 29

right it translates to
1x + 0y = 4 x = 4

and

0x + 1y = -2 y = -2

the point where they intersect is 4, 2

Answer 30

it is pretty magical...

Answer 31

that's awesome. thank you for your help!

Answer 32

np

yw