Question

How do I solve this question?
x + y + z = 12
6x - 2y - z = 16
3x + 4y + 2z = 28

Btw medal is awarded if u help me out :)

Answer 1

use elimination
let x + y + z = 12 be eqn 1
6x - 2y - z = 16 be eqn 2
3x + 4y + 2z = 28 be eqn 3

first thing you do, eliminate "z"
add eqn 1 and 2-->new eqn will be eqn 4
add (eqn 1 times -2) + eqn 3--->new eqn will be eqn 5

then find either x or y using your two new equations..
then you can use substitution to the rest of your solution

Answer 2

Lets use numbers plus ur explanation

Answer 3

Step 1) Can you add the first two equations and tell me what you are getting?

Answer 4

^ yes, do that first

Answer 5

You can also use matrices, and i think is simpler and easier. But above methods are correct also.

Answer 6

Ok

Answer 7

so what you get for eqn 4?

Answer 8

7x - y = 28

Answer 9

Right?

Answer 10

yes!

Answer 11

now next step: multiply eqn 1 by -2

Answer 12

K

Answer 13

I got 4x + z = -8 right?

Answer 14

multiply eqn 1 by -2 ??

Answer 15

No sorry hold on

Answer 16

-2x + 2y + 2z = 24

Answer 17

watch your negatives...

Answer 18

Oh right sorry

Answer 19

so you'll get?

Answer 20

U mean at the end?

Answer 21

multiply eqn 1 by -2,

Answer 22

Ok got that so its the same except its -

Answer 23

yes,, so that will be?

Answer 24

-2x - 2y - 2z = -24

Answer 25

right:)
so next step: add this eqn (-2x - 2y - 2z = -24) to eqn 3

Answer 26

K

Answer 27

Its x + 2y = 4 right?

Answer 28

yes! so that will be our eqn 5

so you decide which variable (x or y) would you like to solve first?

Answer 29

y

Answer 30

Will it make any difference?

Answer 31

ok, so again using eqn 4 and eqn 5 we will use elimination to eliminate "x"

Answer 32

try multiplying eqn 5 by -7

Answer 33

Wait slow down please

Answer 34

no, it will not make any difference:)

Answer 35

Ok I was looking for my 4th equation

Answer 36

eqn 4: 7x-y=28
eqn 5: x + 2y = 4

Answer 37

Yea got u

Answer 38

did you multiply eqn 5 by -7 already?

Answer 39

Yes

Answer 40

sorry if i'm going too fast, i need to go offline now....

Answer 41

I got -7x - 14y = -28

Answer 42

Oh ok

Answer 43

Right?

Answer 44

right:) then add that to eqn 4

Answer 45

I did that

Answer 46

Is y = 0?

Answer 47

RIght!!!!!! (^_^)
so next, uhm substitute y value to either eqn 4 or eqn 5 to solve for x

Answer 48

Lol k thanx sooo much!! U should help me every time I got a question.

Answer 49

lol XD
can you manage now from here?

Answer 50

Hmm...

Answer 51

can you?

Answer 52

Listen if u want to go just go ill figure it out and its an easy step dont worry :)

Answer 53

Yes I can :D

Answer 54

i can stay for 10 more minutes i think

Answer 55

YAY! i like you, you're an easy-learner :)
goodluck in your math, c ya round (^_^)

Answer 56

Sure :) anytime lol

Answer 57

Just one more question

Answer 58

Hold up tho

Answer 59

Im supposed to have 2 numbers or 3? U kno x, y, & z

Answer 60

yeah, you need to find the values of (X, Y, Z)

Answer 61

Oh k got it nvm thanx again :)

Answer 62

I do have another question but since ur leaving ill ask someone else