Solving 3 equations with 3 unknowns

rooney

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Feb 9, 2008
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0=.6x+.3y-z
0=z-.6y+x
0=y+.6x-1962

It has been a while since I've done this sort of algebra, and can't get an answer for any of the variables. I've tried substituting and combining equations, but I never get the correct answers.
 
rooney said:
0=.6x+.3y-z
0=z-.6y+x
0=y+.6x-1962

It has been a while since I've done this sort of algebra, and can't get an answer for any of the variables. I've tried substituting and combining equations, but I never get the correct answers.

first multiply everything by 10 - convert equations to simple numbers:

6x + 3y + 10z = 0 .....................(1)

10x - 6y + 10z = 0.....................(2)

6x + 10y = 19620......................(3)

first subtract (1) from (2) to get

4x - 9y = 0.............................(4)

x = 9/4 * y.............................(5)

Use (5) in (3) to solve for "y"

Use that in (5) to solve for "x"

Use those values in (1) [ or(2)] to solve for "z".

Finally, use all those values in the original equations - to check your answer.
 
Thanks for your help. From your explanation It turns out that one of my coefficients was wrong, but your way of solving the equation was much easier.
 
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