I need to solve this:
6x-5z=17
5x-y+3z=-1
2x+y=-41 I know how to solve problems with all three variables in each equation, but this has me stumped. Please help!

Question

I need to solve this:
6x-5z=17
5x-y+3z=-1
2x+y=-41 I know how to solve problems with all three variables in each equation, but this has me stumped. Please help!

anonymous · Answer

From the first Equation: 6x-5z=17
                                      z=(6x-17)/5

anonymous · Answer

Substitue that in the second equation......

anonymous · Answer

And solve that equation and the third equation

anonymous · Answer

Got it?

hartnn · Answer

find z in terms of x from 1st equation
find y in terms of x from 3rd equation
put both in 2nd equation,u will be left with only x
so u will get x
then put in 1st equation to get z
and in 3rd equation to get y

anonymous · Answer

I'm still not getting it. When I isolate either x or z in the first equation I get a decimal answer, which leads to other decimal answers. I actually have the answers I'm supposed to get (-3, -35, -7), but I don't get them whatever I do!

hartnn · Answer

6x-5z=17
so, 6x-17=5z
so,z=(6x-17)/5
do not simplify this....put it as it is in 2nd equation....try it

anonymous · Answer

Got 23x-y+3z=-4.4....
?

hartnn · Answer

how did u still get y and z
u were replacing y,z in terms of x...so u must have equation only in x...

anonymous · Answer

Dang. Doing it over...

anonymous · Answer

y=-23x+2.4
Substitute it in the third one now?

hartnn · Answer

how did u get that?

anonymous · Answer

5x-y+3(6x-17/5)=-1
5x-y+18x-51/15=-1
23x-y-3.4=-1
23x-y=2.4
y=-23x+2.4

hartnn · Answer

5 is in the denominator,not in numerator...so it won't be 15
let me do it for u
form 1st equation,we have z=(6x-17)/5
from 3rd equation we have y=-41-2x
when we put it in 2nd,we have
5x+2x+41+3*(6x-17)/5=-1
can u solve further for x??

hartnn · Answer

@InTheTardis

anonymous · Answer

Okay, I got x=-1.

hartnn · Answer

let me find x for u
5x+2x+41+3*(6x-17)/5=-1
so 7x+3*(6x-17)/5=-42
so 35x+3*6x-3*17=-42*5
so 35x+18x=-210+51
so 53x=-159
so x=(-159)/53
so x=-3
now tell which step u did not understand,from beginning??

anonymous · Answer

I just wasn't sure what to do with the 6x-17/5. I simplified everything on the left side as best I could; I didn't think to move the variables to the right first.

hartnn · Answer

so did u get all steps now?
or should i explain some steps,which u didn't get??

anonymous · Answer

What are the asterisks? Multiplying?

hartnn · Answer

yup

anonymous · Answer

Why did you multiply everything by 5?

hartnn · Answer

7x+3*(6x-17)/5=-42
|dw:1345435457585:dw|
so that i get rid of the denominator....
by multiplying 5 throughout...