SOLUTION: The last three problems of my HW are stumping me and I've been working on them for 2 hours. Can you solve them but show me the steps you took to get there? Thanks (1)Solve for

Algebra ->  Rational-functions -> SOLUTION: The last three problems of my HW are stumping me and I've been working on them for 2 hours. Can you solve them but show me the steps you took to get there? Thanks (1)Solve for      Log On


   



Question 43021: The last three problems of my HW are stumping me and I've been working on them for 2 hours.
Can you solve them but show me the steps you took to get there?
Thanks
(1)Solve for x, y, and z
8x-y+z=41
4x+2y-3z=42
x-3y+2z=-11
(2)Solve for x, y, and z
x+y+z=0
2x+4y+2z=-4
-x+8y-3z=-16
(3)Solve for x, y, and z
x+y+z=-4
2x+5y+2z=4
-x+8y-3z=50
Thank you

Answer by mszlmb(115) About Me  (Show Source):
You can put this solution on YOUR website!
OK #1:
8x-y+z=41
4x+2y-3z=42
x-3y+2z=-11

8x-y+z=41We want to isolate a variable, -41 and +y on both sides.
8x+z-41=yThat's as far as we go with the 1st equation.
4x+2y-3z=42Here's the magic.  You see the y?  We're going to replace it according to 
our final equation preceeding. 4x+2(8x+z-41)-3z=42simplify, don't lose your head yet! 4x+16x+2z-82-3z=42keep going! 20x-z-82=42 OK back to magic, we have to isolate another variable. +z and -42 on
both sides. 20x-124=zthat's as far as the second equation goes. x-3y+2z=-11Again, replace z with correspondant on preceeding equation.
WAIT! We have another variable we can replace, Y. Let's do that.. [If you haven't
gone completely insane from this crazy process keep it 2gether just a little longer =P] x-3(8x+z-41)+2(20x-124)=-11Having fun yet? SIMPLIFY x-24x-3z+123+40x-248=-11keep going..:D 17x-3z-125=-11Have I lost you yet? If I haven't, I'll give it one more try. Replace
z with its equivalent ;) 17x-3(20x-124)-125=-11If you're still here we're almost done. SIMPLIFY 17x-60x+372-125=-11simplify! -43x+247=-11(; our first solvable equation! -247 both sides -43x=-258divide by -43 x=6PHEW! an even number! now plug it in to various equations.. SPECIFICALLY the equation with X and another variable: z=20x-124 replace x with equivalent, 6: z=20(6)-124solve: z=120-124=-4. Plug that in the equation with z, x, and another variable: 8x+z-41=y plug in 6 for x and -4 for z. 8(6)+(-4)-41=ythis is fun, huh? solve: y=48-4-41=3sarcastic woohoo. WOOOO!!!!! WE'RE DONE!! x=6 z=-4 y=3 I would not love to do the other problems with you, but will not for a few reasons.
The first being my concern for my own sanity, the second my concern for your own,
and the last, so you can see if you yourself understand how to solve them. try it
on your own! EMAIL or IM me for questions.. good luck.