Question

4x -4y +13z=-30
22x -22y +73z=-168
35x -35y +117z=-269

Answer 1

Fun.....

Answer 2

really?

Answer 3

4x -4y +13z=-30=x=13z/4+y-15/2

Answer 4

Got to do elimination. Pick two pairs of equations. Eliminate z. Then, solve for x and y. Then, substitute to figure out z.

Answer 5

22x -22y +73z=-168=x=-73z/22+y-84/11

Answer 6

not my idea of fun, but hey,
here is the answer, although this will not help you on a test
http://www.wolframalpha.com/input/?i=4x+-4y+%2B13z%3D-30%2C22x+-22y+%2B73z%3D-168%2C+35x+-35y+%2B117z%3D-269

Answer 7

35x -35y +117z=-269=x=-117z/35+y=269/35

Answer 8

I would post my steps, but you would hate me afterwards.

Answer 9

His solving it using matrices.

Answer 10

No, not using matrices

Answer 11

or the reduction method

Answer 12

Using my own method

Answer 13

....why don't you want to use matrices?

Answer 14

Using matrices to teach this type of linear equation solving is a BAD idea. Matrix method is fine as a subsequent lesson to generalize the solution for N variables.

Answer 15

Romero, why don't you post your matrix steps...lol

Answer 16

So you rather use substitution?

Answer 17

wait how is row reduction different from using matrices?

Answer 18

I prefer using the most agonizing set of steps

Answer 19

ouch, agonizing is right

Answer 20

lol

Answer 21

All that work just to find out no solution. I'm disappointed.

Answer 22

rref a matrix would be my idea as well

rref{{4, -4, +13, -30},{22, -22, +73, -168},{35, -35, +117, -269}}

http://www.wolframalpha.com/input/?i=rref%7B%7B4%2C+-4%2C+%2B13%2C+-30%7D%2C%7B22%2C+-22%2C+%2B73%2C+-168%7D%2C%7B35%2C+-35%2C+%2B117%2C++-269%7D%7D

infinite solutions

Answer 23

To my thinking, the solution technique may be dictated by the Instructor or the instructions. I don't know how far along CW is in his studies. If CW has never heard of matrices, then a solution based on them will mean little, I would think.

Take a look at this online solver: http://www.analyzemath.com/Calculators/Calculator_syst_eq.html

Answer 24

amistre,you should have did it by hand.