Time For Math!! (Level: Pre-Cal/Algebra)

[Young Shimaiuskoo Doh]

First of all, I know some of you chaps may be out of school and may not want to see another textbook until the next day...

Oh well!!

Are there any chaps in the Guild Academy, skilled in the ways of Mathematics, preferably Pre-Calculus and Algebra? Young Durr, here, is in need of some assistance and would love it if any of you Mathematical-chaps could lend him a hand...or foot...or nose...or dollar...whatever you can spare!

[Valodim]

that is very vague. can you be more specific?

[Young Shimaiuskoo Doh]

I thought you chaps were waiting for me to post something...

Sorry about that!!
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Heres a problem:

3x³ = 3x² + 60x

My brain is on "Deeply Fried" right now, and would really like it if any chaps could help out!

[Valodim]

3x³ = 3x² + 60x	| /x
3x² = 3x + 60	| -3x³
0 = -3x² + 3x + 60	| *(-1) /3
0 = x² -x -20

[Young Shimaiuskoo Doh]

You are truly a legend, Valodim, truly a legend. (Young Footlecum Durr will grow to be like Valodim one day...)

Thanks, mate!!

I'll be returning to this thread from time to time if I have more questions!!

Actually, I have one, now!!

Have any of you chaps ever heard of Point-Interval Notation?

[hjk]

3x³ = 3x² + 60x	| /x
3x² = 3x + 60	| -3x³
0 = -3x² + 3x + 60	| *(-1) /3
0 = x² -x -20

Shouldn't that have been solved further (didn't read whole thread)

- I reformed the equation making it this
3x³ - 3x² - 60x = 0

- Then I factored out the "3x" leaving me with
3x(x² - x - 20) = 0

- Then I took out the "3x" (because it doesn't matter) and factored the rest
(x² - x - 20) = 0
(x-?) (x+?') = 0

   5 * 4 = 20 so
? = 5 and ?' = 4
and that allows for a "0" answer

- Plug that in and you have this:
(x-5)(x+4)
(x² - x - 20)

- This would mean that when x = 5 or when x = -4 the equation equals zero (asx seen on a graph if I haven't made a mistake while typing)

**Check the answer by plugging the numbers (x = 5 or x = -4) into the original equation. I will do the same after finding a calculator.

[Young Shimaiuskoo Doh]

Thank you very much, fellow Sonic-Avatar, Jango's Godzilla!!

The solutions "x = 5" and "x = -4" check perfectly!

I'm still trying to figure out the Point/Interval Notation part of it, but in the meantime, here's an inequality:

t² - 9t > 0

I'm thinking I should transpose the "9t" to the other side of the arrow and square both sides...just a guess...

[hjk]

Thank you very much, fellow Sonic-Avatar, Jango's Godzilla!!
The solutions "x = 5" and "x = -4" check perfectly!

NP. Took this about 2 yrs ago (early for my age but my memory is usually bad)

Case in Point:

I'm still trying to figure out the Point/Interval Notation part of it, but in the meantime, here's an inequality:
t² - 9t > 0
I'm thinking I should transpose the "9t" to the other side of the arrow and square both sides...just a guess...

I don't even remember. I'm tempted to bring the 0 over but then I can't remmber what to do with the "inequality."

I KNOW, however, that the answer is:
t < 0
t > 9
*unneeded*................ t != 0

[Valodim]

hjk: Yes, by using a regular quadratic formula. In case you never heard of that one - it's key to solving quadratic equations, and you will sooner or later be expected to know it. Learn it, now.

I never heard of Point/Interval Notation. I do know Interval Notation.
t² - 9t > 0
t - 9 > 0
t > 9

solution interval: { t | t > 9 }

alternate way of writing: (9, infinity]
Note here that the ( indicates an exclusive boundary, while ] means inclusive. so [3, 5) would mean 3 <= x < 5. You can use this in MUGEN, too:

trigger1 = time = [3, 5)

would trigger if time was 3 or 4, but not 5.

[hjk]

hjk: Yes, by using a regular quadratic formula. In case you never heard of that one - it's key to solving quadratic equations, and you will sooner or later be expected to know it. Learn it, now.

Yes, I know it. God, after sending that PM I slapped myself. I wasn't thinking properly while writing it and meant to put at the end that I think there is something that I'm not thinking about, or else I looked deeper into the equation than what was needed. Admittedly, I don't understand what you mean by making that post, BUT, I'm sure there is something that, again, I've neglected to think of.

I never heard of Point/Interval Notation. I do know Interval Notation.
t² - 9t > 0
t - 9 > 0
t > 9
solution interval: { t | t > 9 }

Does my additional answer of "t < 0" check out as well?

[Young Shimaiuskoo Doh]

Seriously, chaps, if Harry Potter were a Math Wizard like you shipmates, his skills couldn't rival half of you guys.

How did you come to the conclusion of (9, infinity] without a number-line? (Open question to anybody.)

[Valodim]

Ah whoops. you're right t < 0 is true as well.

t² - 9t > 0
t(t-9) > 0

one: /t
t-9 > 0
t > 9

two: /(t-9)
t < 0

The > becomes a < with that operation. Do not ask me what the specific conditions for that to happen are, I can't remember. It just fits in this case.

[hjk]

The > becomes a < with that operation. Do not ask me what the specific conditions for that to happen are, I can't remember. It just fits in this case.

Thanks Val. i'm going to see if some old texts of mine may give the answer to why that is.
Props my friend.

[Young Shimaiuskoo Doh]

Thanks for your help so far, chaps, I really appreciate it!
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Here's a Square Root version:

SqR(2x + 3) < 5

The SqR means "Square Root," and anything inside the parenthesis is in Square Root form. I don't know to post a Square Root...

I tried out the equation and got: x < 11

[Valodim]

(2x+3)^1/2 < 5
2x + 3 < 25
2x < 22
x < 11

[Spoonman]

This I like.

Here's one for all of you:


X^x=2

X=?

[( ﾟ oﾟ) It's Urza!]

*Ahem*
This will help if you are in a rut.

[Young Shimaiuskoo Doh]

Ah, Chap-Urza!! Thanks for the link!!


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Here's a problem with absolute value:

|x - 6| < 8

[Young Shimaiuskoo Doh]

Sorry for using Double Post Power, chaps, but I really need some help...

[Ohsky]

now this remembered me why i hate maths.... well i never was good at them so....