Question

solve for a,b,c
(a + c)(a - c) + (b+2c)(b - 2c) = 2015
with a,b,c are natural number

Answer 1

@rational
is there a solution satisfied for this problem ?

Answer 2

yes
a = 2
b = 56
c = 15

satisfies the given equation

Answer 3

really ? wait i'll check it ...

Answer 4

whats the full question ?

Answer 5

waw, that's correct! how do you get that ? by trials ?
the question is find the solution a,b,c

Answer 6

and find the value of a + b - c
i think if we got a,b, and c so just distribute all number to it

Answer 7

there are plenty of solutions

Answer 8

```
2 56 15
4 98 39
6 68 23
8 86 33
12 46 7
16 42 1
18 44 7
18 56 17
22 44 9
24 38 1
28 66 25
28 94 39
32 46 15
34 48 17
34 92 39
36 58 23
36 62 25
38 24 1
42 16 1
44 18 7
44 22 9
46 12 7
46 32 15
48 34 17
56 2 15
56 18 17
58 36 23
58 64 33
58 84 41
62 36 25
62 76 39
62 96 47
64 58 33
66 28 25
68 6 23
72 94 49
76 62 39
84 58 41
86 8 33
92 34 39
94 28 39
94 72 49
96 62 47
98 4 39
```

Answer 9

what, there are many solution .... can we solve it by some trick anyway ?

Answer 10

even if we solve a,b,c there is no single answer for a+b-c

Answer 11

there is something wrong with the question :/

Answer 12

ok, the question is in indonesia language... if i transleting in english it like :
if a^2 + b^2 - 5c^2 = 2015 than what is the value of a + b - c with a,b, and c are natural number.
sorry my english so bad :(

Answer 13

did u use computer program to get all solution that ?

Answer 14

your english is fine

Answer 15

yes i used program, can u take a screenshot of question and attach

Answer 16

can u speak indonesia ? atleast you understand it :)

Answer 17

I'll try please attach the screenshot if psble

Answer 18

mau tanya nih kak. jika 2015=a"+b"-5c" untuk suatu bil asili a,b,c maka nilai a+b-c=... " maksudnya pangkat 2 trimaksh sblmya
i was copy vaste all statement... i cant attach the screeshot because there is trouble with my keyboard

Answer 19

that is the question from one of the fb group special to discuss olympiad problems

Answer 20

in my country, indonesia.
https://www.facebook.com/groups/pencintamatematika/

Answer 21

Okay I am convinced the question is incomplete as there is no unique solution but the question wants to find an unique value for the expression a+b-c.

Answer 22

ok, thank you very much... btw, what program did you use ?

Answer 23

i was use through wolfram, but the result is c is not integer

Answer 24

click execute

http://goo.gl/xHOSgR

Answer 25

i done. then ?

Answer 26

look at bottom screen

Answer 27

click execute again..
nothing harm..

Answer 28

do u see something like this
http://gyazo.com/06841e8a60e0ba1138d96816c92cbb60

Answer 29

yes, i see but if execute tools is clicked, nothing result out. maybe my laptop not support or my conection is very slow

Answer 30

nothing like that, u look at bottom of screen

Answer 31

out will be displayed at bottom part..

Answer 32

nothing the green secreen like you posted --"

Answer 33

try this maybe

keep looking at bottom part while clicking "Execute"
http://goo.gl/6dzXtM

Answer 34

you may have to drag the green window up to see the output

Answer 35

yes, i did. now the green screen is out now :)
but there is no numbers (result)

Answer 36

click execute again

Answer 37

i clicked the execute more 10 times, but no result here :)

Answer 38

do you see this
http://gyazo.com/1e1020c99f5a708b7f65bf59a9eb9494

Answer 39

we can do skype if you have it

Answer 40

or teamviewer

Answer 41

yes in the pic you posted but no in the program
i think i need going to rental net which has high speed internet to see good result. thanks

Answer 42

u dont have teamviewer ?

Answer 43

no, i dont have

Answer 44

if you want you may install it from here
http://download.teamviewer.com/download/TeamViewer_Setup_en.exe