Binomials....I Don't Get It

[Nailzberg]

Any mathletes wanna help me out and solve for x?

[Fenris]

1. Damn math jokes!

Binomials I can do. Trinomials present more of a problem. Monomials, however, are fun!

[Goldeneye]

2. Like foiling?

I love that stuff.

[dsc]

3. By binomials do you mean the distibution

or simply solving an equation such as (x + 6)(x + 12) = 36

[Nailzberg]

7. Well, actually I just wanted to be an ass.

But I figure y'all know that.

[Zing Zing Zingbah]

8. For a problem like this you could use the

Quadratic Equation to solve for x.

[gtp1976]

12. x=9 btw. hehe n/t

[Zing Zing Zingbah]

13. Actually...

(x+6)(x+12) = 36

No way is the answer is x = 9.

Plug in x = 9 into the equation and see what you get.
(9+6)(9+12)=(15)(21)=315

OK, I think you were kidding when you gave that answer. I'm just going to solve this anyhow because I'm a major geek.

(x+6)(x+12) = x^2 + 6x + 12x + 72 = x^2 + 18x + 72 = 36

x^2 + 18x + 36 = 0

Use the Quadratic formula to find the roots, which will be the answer.

for ax^2 + bx + c = 0

x =( -b +|- sqrt(b^2 - 4ac))/2a

a = 1 b = 18 c = 36

x = (-18 +|- sqrt(18^2 - 4(1)(36)))/2(1)
x = (-18 +|- sqrt(180))/2
x = -9 +|- 3/2*sqrt(20)
x = -9 + -1.5*sqrt(20) and x = -9 + 1.5*sqrt(20)
x is about -15.7 and -2.3

Check x = -9 + 1.5*sqrt(20) by substituting into original equation
(-9 + 1.5*sqrt(20)+ 6)(-9 + 1.5*sqrt(20) + 12)=
(-3 + 1.5*sqrt(20))(3+ 1.5*sqrt(20)) =
-9 + 4.5*sqrt(20) + -4.5*sqrt(20) + (1.5)(1.5)(sqrt(20))(sqrt(20))=
-9 + 45 = 36

Check x = -9 + -1.5*sqrt(20) by substituting into original equation
(-9 + -1.5*sqrt(20) + 6)(-9 + -1.5*sqrt(20) + 12)=
(-3 + -1.5*sqrt(20))(3 + -1.5*sqrt(20))=
-9 + 4.5*sqrt(20) + -4.5*sqrt(20) + (-1.5)(-1.5)(sqrt(20))(sqrt(20))=
-9 + 45 = 36

Thanks for all the fun math problems. I don't get to do this kind of crap any more being a stay at home mom.

[gtp1976]

17. My mistake...

...I read (x+6)+(x+12)= 36 in which case 9 would = x, rather than (x+6)times(x+12)=36.

[Zing Zing Zingbah]

18. I see where you got your answer now...

That makes sense. :)

I just noticed that I could have written
3/2sqrt(20) as 3sqrt(5). That would have been a lot simplier, and easy to read. It doesn't really matter anyhow, since they are the same number. I doubt anyone else cares either. :)

[KG]

4. simultaneous equations left a smoke crater in my mind.

:nuke:

[Zing Zing Zingbah]

10. I love solving simultaneous equations.

Augmented matrices are especially useful when solving simultaneous equations. There are tons of applications for simultaneous equations in engineering and computer science (3D Graphics, Robotics, etc.)

[LynzM]

11. Ooh, gobzillions of applications....

I was an electrical engineering student, once.... :)

[Zing Zing Zingbah]

14. Yeah..

I took electrical engineering courses too. I was a computer engineering major, which is kind of a cross between electrical engineering and computer science.

[LynzM]

15. A lot of hardware?

That's what CE ended up being at my school... I kind of wish I'd gone the route of CS/CE, now. I got into database stuff/programming after I left school, and I really enjoy that.

[Zing Zing Zingbah]

16. Yeah.. but a lot of programming too. n/t

[Emops]

5. Crap like this was why I dropped my minor in statistics.

And calculus is a thousand times worse.

[Zing Zing Zingbah]

6. Yeah... it's just using the distributive property...

(a+b)(c+d)

An easy way to see this is to use substitution first. Say substitute e in for c+d.

e = c+d

Now use the distributive property
(a+b)e = ae + be

OK, now substitute c+d back in for e.

a(c+d) + b(c+d)

Notice you have to do distributive property two more times.

ac + ad + bc + bd

The foil technique is just a short cut to getting the same results.

[Orsino]

9. "God made gay sex, not 3 + x."

...should anyone desire a mindless slogan for his next parade.