once again substitution! can anyone help?

x/y-y/3=5/6

x/5-y/4=-13/10

solve by substitution

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- August 12th 2010, 12:32 PMmafai44solve by substitution
once again substitution! can anyone help?

x/y-y/3=5/6

x/5-y/4=-13/10

solve by substitution - August 12th 2010, 12:53 PMArchie Meade
- August 12th 2010, 01:12 PMmafai44
so sorry lol i wrote the equation wrong x/2-y/3=5/6

x/5-y/4=-13/10 - August 12th 2010, 01:25 PMyeKciM
same thing :D as "Archi meade" wrote there, just now with different numbers :D

multiply firs with 6 and second with 20

now i u can go as you wish :D

first one multiply with 4 and second with (-3) (and then sum them )

rest you know :D

or u can :

and put in second and solve for "y" :D:D:D and so on for x...

P.S. you don't need to do that this way (that's up to you, and with practice u can decide better how and what would you do, so that you have a less work, and to keep it simple... don't complicate it to much :D )

Edit: corrected that "6" and "20"... i really don't know from where and when did i type that :D:D:D:D - August 12th 2010, 02:10 PMArchie Meade
Typo yeKciM !

3x-2y=5 - August 12th 2010, 02:16 PMyeKciM
aaaaah :D

thank you , i'll fix it now :D - August 12th 2010, 02:52 PMmafai44
if anyone can do it once more i got the last one wrong lol i noticed the edit after i answered it

x/2-y/3=5/6

x/5-y/4=-71/10 - August 12th 2010, 03:09 PMyeKciM

here's using substitution :

first one multiply with (6) and second with (20) :D and you will get :

now from any ( i'll do first ) you can express either "x" or "y" (i'll do "x" )

now that "x we put in second equation ...

now multiply with 3 :

now that "y" we will put in first equation :D

P.S. what ? now second equation is with -71/10 , where did go -13/10 ?