SOLUTION: Hello! I posted this problem before, but nobody solved it. I'm really having trouble with this. Please help! x + 2y + 16z = 20 3x + 6y - z = 23 4x + 8y + 2z = 18 It d

Algebra ->  Coordinate Systems and Linear Equations  -> Lessons -> SOLUTION: Hello! I posted this problem before, but nobody solved it. I'm really having trouble with this. Please help! x + 2y + 16z = 20 3x + 6y - z = 23 4x + 8y + 2z = 18 It d      Log On


   

Question 10830: Hello! I posted this problem before, but nobody solved it. I'm really having trouble with this. Please help!

x + 2y + 16z = 20
3x + 6y - z = 23
4x + 8y + 2z = 18

It doesn't matter which method you use to solve this system. Just please show me all the steps. Many thanks ahead!

Answer by longjonsilver(2297) About Me  (Show Source):
You can put this solution on YOUR website!
don't you realise how tedious matrices are? lol I hate them! I spent YEARS studying at uni doing damn matrices and linear algebra.

Anyway, here are 2 solutions ;-):

1. Gaussian Elimination:


OK, 3 times first row subtracted from second row
and 4 times first row subtracted from third row
gives



Now, third row looks fine..will give z=1, but the second row looks wrong to me. I would go back to the question and check the numbers.

2. cramer's rule:
(look on my Lessons for help on this)
I wont do the working either, as i think your second equation is wrong.

jon.