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Mathematics 15 Online
geerky42 (geerky42):

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geerky42 (geerky42):

@DarkBlueChocobo

geerky42 (geerky42):

\(\dfrac{2x}{4}-\dfrac{3}{4}\quad\Longleftrightarrow\dfrac{2x-3}{4}\)

OpenStudy (darkbluechocobo):

Hay there

OpenStudy (darkbluechocobo):

so then I went

OpenStudy (darkbluechocobo):

\[\frac{ 2x-3 }{ 4 }=\frac{ 10-15x }{ 6 }\]

geerky42 (geerky42):

Yes, then you cross-multiply

OpenStudy (darkbluechocobo):

\[12x-18=40-60x\]

OpenStudy (darkbluechocobo):

\[72x-18=40\]

geerky42 (geerky42):

yeah

OpenStudy (darkbluechocobo):

\[72x=58\]

geerky42 (geerky42):

Is that enough to tell what kind of equation it is?

geerky42 (geerky42):

you can tell that x is going to equal something, so it wont be indentity.

geerky42 (geerky42):

two other options are conditional equation and inconsistent equation

OpenStudy (darkbluechocobo):

Inconsistant i believe?

geerky42 (geerky42):

conditional equation true for certain value of x, where if you simplify equation, you end up with x=4 or something inconsistent equation false equation, where you cannot solve for x.

OpenStudy (darkbluechocobo):

Oh so conditional is just like a usual equation that works out ?

geerky42 (geerky42):

If you have something like x+1 = x+2, it's inconsistent equation because you end up with 1=2

geerky42 (geerky42):

yeah

OpenStudy (darkbluechocobo):

lel wow the facepalms are coming out today boys

OpenStudy (darkbluechocobo):

1c. 0=8 so this is false or inconsistent?

geerky42 (geerky42):

pretty much both

OpenStudy (darkbluechocobo):

I am having many issues on 2a

geerky42 (geerky42):

inconsistent equation is kind of fancy way to say false equation lol

geerky42 (geerky42):

you would need to combine fraction on right side. To do so, you need to get denominator to be same

geerky42 (geerky42):

you have \(y-2\) and \(y+1\) So you just multiply numerator and denominator by \(y+1\) for first fraction and \(y-2\) for second

geerky42 (geerky42):

\[\dfrac{1}{y-2}-\dfrac{2}{y+1}\quad\longrightarrow\dfrac{y+1}{y+1}\cdot\dfrac{1}{y-2}-\dfrac{2}{y+1}\cdot\dfrac{y-2}{y-2}\]

geerky42 (geerky42):

Does that make sense? Basically you just need to get denominator to be same, so you just multiply numerator and denominator by something that would get you to desired denominator

geerky42 (geerky42):

kinda hard for me to explain lol

OpenStudy (darkbluechocobo):

so 1/(y+1)(y-2) - 4/(y+1)(y-2) ?

geerky42 (geerky42):

\[\dfrac{y+1}{y+1}\cdot\dfrac{1}{y-2}-\dfrac{2}{y+1}\cdot\dfrac{y-2}{y-2}\\~\\= \dfrac{y+1}{(y+1)(y-2)} - \dfrac{2(y-2)}{(y+1)(y-2)}\\~\\=\dfrac{y+1-2(y-2)}{(y+1)(y-2)}\]

geerky42 (geerky42):

ok let's start with something simply. \(\dfrac{1}{6}+\dfrac{1}{2}\) How can we combine fraction here?

OpenStudy (darkbluechocobo):

multiply by 3/3

OpenStudy (darkbluechocobo):

so 1/6+1/2*3/3

OpenStudy (darkbluechocobo):

so you would get 1/6+3/6

geerky42 (geerky42):

right, so for problem 2a. it's same idea, just with variable.

geerky42 (geerky42):

get what I am saying here?

OpenStudy (darkbluechocobo):

Yes I do its just weird for me to visualize and see it right away t-t idk why

geerky42 (geerky42):

because it's something new for you, I guess?

OpenStudy (darkbluechocobo):

Well like the bigness of the equation kinda like put me in my place kinda deal

geerky42 (geerky42):

ok, so now we have \[\dfrac{y+1-2(y-2)}{(y+1)(y-2)}\] simplify numerator

OpenStudy (darkbluechocobo):

\[y+1-2y+4\]

geerky42 (geerky42):

CLEP test seem little harsh lol...

geerky42 (geerky42):

don't forgot combine like term

OpenStudy (darkbluechocobo):

yeh was just showing steps

OpenStudy (darkbluechocobo):

-y+5

OpenStudy (darkbluechocobo):

It does seem harsh :/ I'm gonna like work myself to the point of no return so I do well on it . I want this

geerky42 (geerky42):

Right. Now cross multiply \[\dfrac{7}{y^2-y-2} = \dfrac{-y+5}{(y-2)(y+1)}\longrightarrow~?\]

OpenStudy (darkbluechocobo):

so we have to do the same with the other side then get (y-2)(y+1) as denominator?

OpenStudy (darkbluechocobo):

oh i guess we dont

geerky42 (geerky42):

Not really. denominator doesn't matter if they are on different side of equation.

OpenStudy (darkbluechocobo):

\[y^2(-y+5) ,-y(-y+5),-2(-y+5)\] would this work?

OpenStudy (darkbluechocobo):

so I got -y3 + 5y^2 y^2 + 5y 2y+10

OpenStudy (darkbluechocobo):

before combining

geerky42 (geerky42):

-y^3 + 5y^2 y^2 - 5y 2y-10

OpenStudy (darkbluechocobo):

damn i messed up multiplying

geerky42 (geerky42):

you just messed up with +/- signs

OpenStudy (darkbluechocobo):

\[-y^2+6y^2-3y-10\]

geerky42 (geerky42):

yeah

OpenStudy (darkbluechocobo):

now the other side

OpenStudy (darkbluechocobo):

let me delete that i need to slow down

OpenStudy (darkbluechocobo):

7(y+1) 7(y-2) 14y+7, 14y-14 14y+14y, 7-14

geerky42 (geerky42):

none. left side should start with \(7(y+1)(y-2)\)

OpenStudy (darkbluechocobo):

so just keep it as is o.o?

geerky42 (geerky42):

So firstly, you expand \((y+1)(y-2)\)

OpenStudy (darkbluechocobo):

why not work out?

geerky42 (geerky42):

You only distribute something with plus sign. \(a(b+c) = ab+ac\) But \(a(bc) = abc\)

OpenStudy (darkbluechocobo):

Alrights

geerky42 (geerky42):

make sense?

OpenStudy (darkbluechocobo):

Yes it does

OpenStudy (darkbluechocobo):

y^2+-2y+y-2?

geerky42 (geerky42):

Yeah

OpenStudy (darkbluechocobo):

so we have \[y^2-y-2=-y^3+6y^2-3y-10\]

geerky42 (geerky42):

you forgot 7

geerky42 (geerky42):

\[7(y^2-y-2)=-y^3+6y^2-3y-10\]

OpenStudy (darkbluechocobo):

damn

OpenStudy (darkbluechocobo):

so do we expand it out with 7 now?

geerky42 (geerky42):

yup

geerky42 (geerky42):

\[7y^2-7y-14=-y^3+6y^2-3y-10\]

OpenStudy (darkbluechocobo):

I got that

geerky42 (geerky42):

now take all terms to right side; \(0 = -y^3-y^2+4y-4\)

OpenStudy (darkbluechocobo):

can confirm got that after working out

OpenStudy (darkbluechocobo):

lel sorry I doing this in a note book :p

geerky42 (geerky42):

know what to do from here?

geerky42 (geerky42):

Notice something you can factor out? Hint: \[0 = \boxed{-y^3-y^2}+\boxed{4y-4}\]

OpenStudy (darkbluechocobo):

we can simplify ?

OpenStudy (darkbluechocobo):

oh you asked lol

geerky42 (geerky42):

Oops should be \(0 = -y^3-y^2+4y+4\)

OpenStudy (darkbluechocobo):

would we simplify the y's?

geerky42 (geerky42):

well, actually we try to factor, so we can easily figure out solutions.

OpenStudy (darkbluechocobo):

-1(y^2+4)(y+1)

OpenStudy (darkbluechocobo):

Would that be how we factor it?

geerky42 (geerky42):

close. should be \((y+1)(4-y^2)\)

geerky42 (geerky42):

Then you can factor \(4-y^2\)

geerky42 (geerky42):

or you can "factor out" -1 from \(4-y^2\) So you would have something like \((-1)(y^2-4)\)

OpenStudy (darkbluechocobo):

-y^2+4. Doesnt this just put us back where we were?

geerky42 (geerky42):

Yeah, just to make it slightly easier to factor out, but never mind.

geerky42 (geerky42):

factoring -1 out is just optional.

geerky42 (geerky42):

You got \(0 = (y+1)(2-y)(y+2)\)?

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