Question

Solve for w, x, y, & z.
w+x+y+z=18
w=x+y+z
w+x-y+z=6
2w=3y
2x+y=8

Answer 1

w+x+y+z=18 -(1)
w=x+y+z -(2)
w+x-y+z=6 -(3)
2w=3y -(4)
2x+y=8 -(5)

Sub. (2) into (1) to solve w.
w+w=18
w = ...?

Answer 2

@wendy76 ?

Answer 3

ok hold on

Answer 4

Better off learning linear algebra lol.

Answer 5

@wendy67 What have you got for w?

Answer 6

ok wait sub 2 into 1? on what equation?

Answer 7

@Kainui i'd be glad too but sadly i am taking math 2 but starting with math3 so we took a huge leap foward in math

Answer 8

w+x+y+z=18 -(1)
w=x+y+z -(2)
w+x-y+z=6 -(3)
2w=3y -(4)
2x+y=8 -(5)
Actually, I labelled the equations with (number)
So,
Sub. (2) into (1) means sub the second equation into the first one.
Since w=x+y+z (from the second equation)
and w+x+y+z=18 (from the first equation)
Sub x+y+z = w into the first equation and you'll get
w + w = 18
Understand?

Answer 9

oh im sorry didnt really understand what you meant by the #s on the side and yea i got it now so let me try then..

Answer 10

It's okay. I'm sorry... I should have explained it.

Answer 11

No your fine, and i got 2x+2y+2z=18

Answer 12

Hmm..... How did you get that?

Answer 13

ok so since w=x+y+z (2nd eq.) i plugged into the first:
(x+y+z)+x+y+z=18
and got that^

Answer 14

Well.... You can do so... but that doesn't make it easier...
Instead you can do it in this way...
w=x+y+z (2nd eq.)
That means x+y+z =w. Put it into the first one:
w + (w) = 18..
Does it make sense to you?

Answer 15

hmm does it mean that x,y,x got canceled and your left with w?

Answer 16

*z

Answer 17

Not really, but substitute x+y+z = w into the equation..

Answer 18

so if i substitude would it give me x+y+z+x+y+z=18?

Answer 19

If you sub w = x+y+z, yes.
But you can do it in another way!
Since x+y+z = w!

Answer 20

ooooh i get it now so it WOULD be
w+(w)=18
2w=18
w=9
?

Answer 21

Yes!!!

Answer 22

Now, consider the 4th equation.
2w=3y
Sub. w = 9 (which you've found) into the fourth equation. You can get the value of y. Can you do it?

Answer 23

yes i already did all of them a got
w=9
x=1
y=6
z=2

Answer 24

*and

Answer 25

Yup :)

Answer 26

ok well thank you (:

Answer 27

Welcome :)