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[Stuggernaut]

Ok, been looking at this problem all night with my wife and we can't get it right...

4 + 2 = 5
X X+1

(In case it doesn't look right, it's 4 over X, plus 2 over X+1, equals 5)

 

[Lambtron]

X = 1.

4/1 = 4
2/(1+1) = 2/2 = 1
4+1 = 5

 

[cvxfreak]

Thanks for reminding me why I hate math. Sorry, I just tried the problem and ran into a stump.

 

[nitewulf]

solve for x?
4/x + 2/(x+1) = 5

[4(x+1) + 2x] / [(x)(x+1)] = 5

[4x + 4 + 2x] / [x(x+1)] = 5

[6x + 4] / [x(x+1)] = 5

6x + 4 = 5[x^2 + x]

6x + 4 = 5x^2 + 5x

5x^2 + 5x -6x -4 = 0

5x^2 - x - 4 = 0

use quadratic formula,

x=1 or x=-0.8

 

[Particle Physicist]

actually.. lamb. your answer is not completely correct.


x = 1

and

x = - 4/5


how to solve:

multiply both sides by x(x+1)..

things cancel out.. and you are left with

(5x+4)(x-1)=0


edit



doh! too slow.

 

[Stuggernaut]

hmmm...see the annoying part is that her book (wife's homework) gives the answer but we have no idea how it got the answer...lol

They say the answer is

X = 1, x = -4/5

I get the answer of x = 1, but I don't get the other one...

 

[ShyGuy]

never mind, i f'ed up lol

 

[Particle Physicist]

never mind, i f'ed up lol

yes you did... and i saw it .

 

[snapty00]

Gah damn. My brain has rotted since high school. There was a time when I ate problems like that for breakfast. Now, shit like that seems like the end of the world.

 

[Stuggernaut]

ok ok...got it to (5x+4)(x-1)=0

then what??

She is frustrated and making simple mistakes, and I haven't done math for 2-3 years!

 

[Pochacco]

Gah damn. My brain has rotted since high school. There was a time when I ate problems like that for breakfast. Now, shit like that seems like the end of the world.

Me too. Not just with math, but everything! Chemistry, Biology, Physics, History facts, Psychology, etc. etc.

It's a good thing 90% of what we learn in school is absolutely useless in real life!

 

[ShyGuy]

yes you did... and i saw it .

lol, i was busy typing my incorrect answer when i clicked submit and realised my mistake with the 'correct methods' above, damn GAF, makes ppl not think properly before posting LOL

 

[nitewulf]

multiply it out using FOIL.

5X * X -1*5X + 4*X -4*1 = 0 (where * = multiplication)

5X^2 (5x squared!) - 5X + 4X - 4 = 0

5X^2 - X - 4 = 0

then just use the quadratic formula to solve it, do a google search for it.

the formula is 2nd order (x to the 2nd power) therefore it has 2 solutions.

 

[cvxfreak]

You people who are good at math have my full blown respect. I envy your skills in the easy, yet extremely difficult subject from hell. I've got the English, science and history down... but no dough for math.

;_; =/

 

[GaimeGuy]

ok ok...got it to (5x+4)(x-1)=0

then what??

She is frustrated and making simple mistakes, and I haven't done math for 2-3 years!

Solve each term for x=0. ( that means solve for x-1=0 AND 5x+4=0)

first, let's solve x-1=0
(x-1)+1=(0)+1
x=1

Now, let's solve 5x+4=0

(5x+4)-4=(0)-4
5x=-4

(5x/5)=(-4/5)

x=-4/5

There you go.

 

[Lambtron]

Fuck the quadriatic formula! I hate that thing. I used to rock shit at algebra, but always hated the quadriatic formula.

I just figured out 1 in my head and posted it. I didn't want to stray youse guys in the wrong direction!

 

[ShyGuy]

Back in my day I was a Maths hotshot, but it's been almost 10 years since I left highschool and haven't looked at Algebra since!

Mathematics are awesome, and fun.

I actually preferred Calculus in highschool, but don't ever mention crap like Physics or Chemistry, I hated those! hahah

 

[GaimeGuy]

multiply it out using FOIL.

5X * X -1*5X + 4*X -4*1 = 0 (where * = multiplication)

5X^2 (5x squared!) - 5X + 4X - 4 = 0

5X^2 - X - 4 = 0

then just use the quadratic formula to solve it, do a google search for it.

the formula is 2nd order (x to the 2nd power) therefore it has 2 solutions.

You did a LOT of unnecessary stuff there. You didn't need to expand. All you had to do was solve 5x+4=0 and x-1=0

 

[nitewulf]

heh i didnt do well in english (lowest grade was 85 for the term, junior year). mostly because in our high school it was a discussion based subject...and i uh...never discussed!

 

[nitewulf]

You did a LOT of unnecessary stuff there. You didn't need to expand. All you had to do was solve 5x+4=0 and x-1=0

true, i went by what i did initially. i didnt factor the polynomial.

 

[snapty00]

What's the first step you guys are doing? I can't even get over that hurdle. :\

 

[nitewulf]

first step is to combine the fractions by finding the GCD, greatest common denominator. which is basically the multiple of X and (X + 1). that would be the standard way to start of.

 

[Stuggernaut]

ok finally it all comes back to me...funny thing is, that problem she is doing is the chapter before they talk about quadratic equations...talk about throwing a wrench into the mix!

She was like "wtf is this??"

lol

Thanks guys! You saved me from the "cranky wife from hell because she sucks at math" syndrome. Would have lasted through tomorrow for sure

 

[ShyGuy]

the first step (and the one I initially made a mistake on) is to look at whatever is "at the bottom of the 'fractions' and then multiply BOTH SIDES with that, that way you'll cancel out all the fractions and end up with whole numbers.

whole numbers are easier to work with.

then u just subtract/add all the integers until you're left with letters ('x' in this instance) and from there u just repeat the steps

er...that wasn't very well explained, but that's how i do things with algebra, it's all about isolating X

 

[Particle Physicist]

ok finally it all comes back to me...funny thing is, that problem she is doing is the chapter before they talk about quadratic equations...talk about throwing a wrench into the mix!

She was like "wtf is this??"

lol

Thanks guys! You saved me from the "cranky wife from hell because she sucks at math" syndrome. Would have lasted through tomorrow for sure

well, you dont need the quadratic to solve this.