Math Is Fun Forum

Heldensheld

Member

Registered: 2006-07-01

Posts: 25

Just need some quick tips on how to solve a tri-simultaneous equation.

So there are these questions I couldn't get. It's taking me a while now so I figured I might need some expertee help. I'll post the tri-equations but I hope you people can take me through it step by step and what ways did you use to solve it.

So here we go!

xy/(x+y) = 1/2       yz/(y+z) = 1/3      and xz/(x+z) = 1/7.

Thanks for your patience, time and help !

mathsyperson

Moderator

Registered: 2005-06-22

Posts: 4,900

Re: Just need some quick tips on how to solve a tri-simultaneous equation.

By flipping the fractions over on each side and then splitting the left side into partial fraction, you can simplify each equation down to:

1/x + 1/y = 2
1/y + 1/z = 3
1/x + 1/z = 7

Hopefully that should be a much easier set of equations to solve. Post again if you still don't get it.

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luca-deltodesco

Member

Registered: 2006-05-05

Posts: 1,470

Re: Just need some quick tips on how to solve a tri-simultaneous equation.

and by quadratic equation

obviously, the second set of values doesnt work, but the first set does.

so, the answer is

did you understand how i did it?

basicly, for the first equation, i rearranged it for the second variable being the subject
then in the second equation, i substituted the rearrange first equation, and then got another rearrange equation for the third variable
then substituting into the last equation, i got a value for x, which i plug into the 2 rearranged equations, for a value for y and z

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