Math question - NEVERMIND!!! Permission to neff thread.

[Scrapster]

Simple algebra question. So simple infact, they don't bother mentioning the technique in my math book.

Equations:

C1 + C2 = 2
-2C1 - 3C2 = 3

Question: Solve for constants: C1 and C2

Isn't there a way to add or subtract equations to solve for more than 1 variable?
I always had a hard time remembering this method in algebra class, and my memory hasn't improved since.

Help?

Scrapster

 

[yakko]

Ok but you have to get used to my neffing.

 

[JW310]

Solve the first equation for C2 in terms of C1, and then substitute that into the second equation to get it all in terms of C1. Solve for C1, and then put back into the first equation to get C2.

[Edit]Or, you can multiply one of the equations by a common factor so that when you add the first one to the second one, you get a coefficient of 0 for either C1 or C2.[/Edit]

Any questions?

JW

 

[johnjohn320]

Well, if constant means what I think it does, then C2 is twice that of C1 (feel free to correct me). So, then
C1+C2=2
.5x+x=2

you go from there, I'm too lazy. And I'm also probably wrong about constants. But anyway, why are you doing your algebra on a saturday night of a long weekend? Youre a better person than me.

 

[johnjohn320]

OH duh, JW is right. I shouldve remembered that.

 

[Scrapster]

You should've remembered that?

DAMN! I don't know why substitution didn't come to my mind. I was thinking about a completely different method.

Thanks JDub.

I feel like an idiot.

Scrapster

 

[johnjohn320]

Me too.

 

[guyver01]

<EDIT> never mind... it didn't work... guess i don't know my math

 

[Scrapster]

Guyver,

Try again.



Scrapster

 

If I have permission, ok!

 

[guyver01]

LOL... just saw it... i did something wrong.. been so long since i hadda solve multivariable equations..

damn calculus... messed up my mind... now i overcomplicate things.

 

[m3lo]

c1+c2=2 }*2 (x2 the whole row #1)
-2c1-3c2=3

2c1+2c2=4
-2c1-3c2=3 (add both rows)

-1c2=7
c2=-7

c1+(-7)=2 (sub in -7 for c2)
c1=2+7
c1=9

 

[m3lo]

i kind of remember my math

what was i smoking?

 

[The Wildcard]

hahaha ahhh, the joys of Algebra. you'd be suprised how the often &quot;Simultaneous Equations&quot; method comes up later on in Calculus and other math such as Differential Equations.

 

[Static911]

dammit, i can't even calculate that despite I can add 1/4, 1/8, 1/16, 1/32 instantly for stocks and I daytrade too! Well, GL in math cuz I always sucked at it

Static911

 

[Scrapster]

The wildcard,

you guessed it. just finished my diff. eqn homework.



Scraps