Thread: basic Solve for x and y problem i'm stuck on.

1. basic Solve for x and y problem i'm stuck on.

Hey all,

I’ve got ‘solve for X and Y’ issues.

….here’s three examples:

133 = 350 - ( (x - 95)^2 + (y - 85)^2 ) * 2

47 = 350 - ( (x - 160)^2 + (y - 85)^2 ) * 2

172 = 350 - ( (x - 128)^2 + (y - 160)^2 ) * 2

I’m building a little “color-selector” website for converting red, green, blue color codes. There are a lot of little sites that do it. I just wanted to build my own for fun. I’ll post the link when finished! My Algebra is all but lost, so any help/Explanation would be much appreciated!

2. Re: basic Solve for x and y problem i'm stuck on.

133 = 350 - √[(x - 95)^2 + (y - 85)^2] * 2

Simplifies to:
√[(x - 95)^2 + (y - 85)^2] = (350 - 133) / 2

Square both sides:
(x - 95)^2 + (y - 85)^2 = [(350 - 133) / 2]^2

Best you can do...any value of x will yield a y value.
Since you have 2 unknowns, you need 2 equations.

3. Re: basic Solve for x and y problem i'm stuck on.

Originally Posted by DenisB
133 = 350 - √[(x - 95)^2 + (y - 85)^2] * 2

Simplifies to:
√[(x - 95)^2 + (y - 85)^2] = (350 - 133) / 2

Square both sides:
(x - 95)^2 + (y - 85)^2 = [(350 - 133) / 2]^2

Best you can do...any value of x will yield a y value.
Since you have 2 unknowns, you need 2 equations.
Thanks DenisB,

I forgot to mention that x and y are both the same for all three equations...

133 = 350 - √( (x - 95)^2 + (y - 85)^2 ) * 2

47 = 350 - √( (x - 160)^2 + (y - 85)^2 ) * 2

172 = 350 - √( (x - 128)^2 + (y - 160)^2 ) * 2

... Is that enough to solve for both? or do i still need x or y?

Thanks!

4. Re: basic Solve for x and y problem i'm stuck on.

Simplify two of the equations like dennisb did, then solve for x and y like you would a normal system. I would use the first two equations because they both have the both have the (y-85)^2 term.

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5. Re: basic Solve for x and y problem i'm stuck on.

Originally Posted by lastplace199
Simplify two of the equations like dennisb did, then solve for x and y like you would a normal system. I would use the first two equations because they both have the both have the (y-85)^2 term.

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So it sounds like I have all I need to solve...

....however it's the "solve for x and y like you would a normal system" bit that I'm stuck on... understand it's basic Algebra, but I'm just embarrassing stuck trying to work it out...:-/

Any help/ references would be great! dennisB got me out to a good start, but don't know how to work it from there with 2 equations to solve for both...