Question

I'm stuck......
Solve the following systems of equations using matrices.

x+y-5z=-18
3x-3y+z=6
x+3y-2z=-13

step by step please -_-

Answer 1

calculator or reduced ?

Answer 2

the answers in ordered pair form. (x,y,z)

Answer 3

are you sure all your numbers and signs are correct? According to http://www.wolframalpha.com/input/?i=x%2By-5z%3D-18+3x-3y%2Bz%3D6+x%2B3y-2z%3D-13 all answers are fractions.

Answer 4

\[\left[\begin{matrix}1 & 1 & -5 \\ 3 & -3&1 \\ 1 & 3 &-2\end{matrix}\right]= \left[\begin{matrix} -18\\ 6 \\ -13 \end{matrix}\right]\]

Answer 5

hmm how to solve how to solve.... agreene do kramers !!

Answer 6

lol, f that!

Answer 7

XD kramers is much easier than say...... doing reduced maybe?

Answer 8

I would never solve any system by matrix unless I were forced to do so.

Answer 9

since they're fractions? lol

Answer 10

throwing them into the calculator is the easier XD

Answer 11

where are you stuck nancy?

Answer 12

x+y-5z=-18
3x-3y+z=6
x+3y-2z=-13
------------------------------

x=5z-18-y
----
5z-18-y+3y-2z=-13
y= 1/2 ( 5-3z)
------
3(5z-18-y)-3( 1/2 ( 5-3z)) +z = 6
3(5z-18-(1/2 ( 5-3z)))-3( 1/2 ( 5-3z)) +z = 6
z=3
-----
y= 1/2 ( 5-3z)
y= 1/2 ( 5-3(3))
y=-2
------
x=5z-18-y
x=5(3)-18-(-2)
x=-1

Solution:
(-1,-2,3)

Matrices, HA!

Answer 13

@MarinaDL, please learn how logic works:

http://www.wolframalpha.com/input/?i=x%2By-5z%3D-18%3B+3x-3y%2Bz%3D6%3B+x%2B3y-2z%3D-13

Answer 14

ouch cold hearted bro, he's out for blood

Answer 15

^_^

Answer 16

I'm a touch drunk atm.

Answer 17

drunken mathematics = awesome

Answer 18

How do you think I survived getting a BA in Math? By being sober? LOL!

Answer 19

drinking while helping with math probably makes you act like a raging genius. "How did you not know that this limit goes to zero. are you that dull "

Answer 20

lol a drunk mathematician could be a comedy act

Answer 21

lol probably!

Answer 22

I think we have something here

Answer 23

But yeah, I would have not survived my Topics classes without Rum/Gin/Beer... it was all non-euclidan geometry/topology... which is REALLY interesting, but also so mind numbingly hard that it makes you question your own existence as an organism with self thought.

Answer 24

spelling fails all up and in that post....

Answer 25

whats the derivative of 2xcos(pi x) too lazyyy lol

Answer 26

\[\frac{d}{dx} ( 2x\cos(\pi x))=2 (\cos(π x)-π x \sin(π x))\]
Product rule - > chain rule kid!

Answer 27

i meant integral lmfao sooo tired

Answer 28

XD

Answer 29

\[\int\limits_{-\pi}^{\pi}x^2+2xcos \pi x+\cos^2 \pi x\]

Answer 30

Why do I deal with you?

Answer 31

@outkast is that really what you mean to integrate? because that can be reduced... by a lot

Answer 32

To agreene: thanks for the example. I figured out it wasn't right, but didn't know how to put it proper way.

Answer 33

Wait no, I was looking at it wrong, you mean that pi and x are in the cos function... eff that noise!

@MarinaDL, No problem <3

Answer 34

yesh i have to integrate this lol

Answer 35

you realize how annoying that integral will be right?

Answer 36

Like... you need to factor it, and then I see atleast 1 integration by parts followed by a trig sub... who knows after that, lol...

Answer 37

haha! Wolfram knows, and shows steps :D

http://www.wolframalpha.com/input/?i=x%5E2%2B2xcos+%28%5Cpi+x%29%2B%5Ccos%5E2+%28%5Cpi+x%29+dx

Answer 38

trig sub?... haha that isn't even all the question

Answer 39

wolfram used trig sub ^_^
It's super effective :D

**not the sqrt(1-x^2)=asin(theta) trig sub... but the let u=random trig stuffs trig sub.

Answer 40

@ ohsnapsitsnancy
A solution to the equations is attached.