Mathematics
20 Online
OpenStudy (firejay5):
Simplify Each Expression. Show work and explain it.
32. m over m^2 - 4 + 2 over 3m + 6
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OpenStudy (firejay5):
Well on #32, I am having trouble multiplying the denominators to make them the same
OpenStudy (anonymous):
"m over m^2 - 4 + 2 over 3m + 6"
\[
\frac{m}{m^2-4}+\frac{2}{3m+6}
\]
OpenStudy (firejay5):
why
OpenStudy (anonymous):
Just use this: \[
\frac{a}{b}+\frac{c}{d}=\frac{ad+cb}{bd}
\]
OpenStudy (anonymous):
I think the + is separating two fractions.
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OpenStudy (firejay5):
yes
OpenStudy (firejay5):
yea
OpenStudy (firejay5):
can you do it with me and then I'll do 33.) my self
OpenStudy (firejay5):
what do you mean?
OpenStudy (firejay5):
Equation editor
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OpenStudy (firejay5):
can we get back to the problem
OpenStudy (firejay5):
or not @Hero
OpenStudy (firejay5):
the example he gave isn't going nowhere for me
OpenStudy (anonymous):
let \(b=m^2-4\) and \(d=3m+6\)
OpenStudy (anonymous):
\[
\frac{m}{m^2-4}+\frac{2}{3m+6}=\frac{(m)(3m+6)+(2)(m^2-4)}{(m^2-4)(3m+6)}
\]
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OpenStudy (anonymous):
@Firejay5 Do you see the pattern?
OpenStudy (firejay5):
Yes? Kind of how did you get that
OpenStudy (firejay5):
I need full out steps, like getting the denominators equal, etc.
OpenStudy (firejay5):
@Mertsj could you help with that
mathslover (mathslover):
hmn .
\[\frac{m}{m^2-4}+\frac{2}{3m+6}\]
Well I think that it would be Ok to factorize both denominators
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OpenStudy (mertsj):
Yes. mathslover will be able to show you.
OpenStudy (firejay5):
@Mertsj you sure
mathslover (mathslover):
\(\color{blue}{m^2-4}\) is in the form of \(a^2-b^2\)
\(a^2-b^2 = (a+b)(a-b)\)
Use the above stated identity to factorize \(m^2-4 \) .
OpenStudy (mertsj):
yes
mathslover (mathslover):
Can you factor \(m^2-4\) @Firejay5 ?
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OpenStudy (firejay5):
yes
mathslover (mathslover):
Can you tell me what would be the factorized form for \(x^2-4\) ?
OpenStudy (firejay5):
(x - 2) & (x + 2)
mathslover (mathslover):
Great! So \(x^2-4 = \color{blue}{(x+2)(x-2)}\)
Now. we have the complete question as :
\(\cfrac{m}{\color{red}{(m+2)(m-2)}}+\cfrac{2}{3m+6}\)
mathslover (mathslover):
Now take 3 common from 3m + 6. What you get?
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OpenStudy (firejay5):
I did the other factorization as well
OpenStudy (firejay5):
3(m + 2)
mathslover (mathslover):
Great! \(\cfrac{m}{\color{red}{(m+2)(m-2)}}+\cfrac{2}{\color{orange}{3(m+2)}}\). Is what we have now.
mathslover (mathslover):
Now take LCM .
OpenStudy (firejay5):
m + 2
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mathslover (mathslover):
Check it again
OpenStudy (firejay5):
and m - 2
mathslover (mathslover):
LCM of \(\cfrac{1}{a+b} + \cfrac{1}{2(a-b)} \) (denominators) is (a+b)(a-b)2
mathslover (mathslover):
Similarly do that there. we have \((x+2)(x-2) \quad\textbf{and}\quad 3(m+2)\) as the denominators
OpenStudy (firejay5):
it would be 3(m - 2) (m + 2)
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mathslover (mathslover):
Yeah . and sorry there for using x on the place of m
mathslover (mathslover):
So I have : 3(m-2)(m+2) as LCM
can you solve the fraction :
OpenStudy (firejay5):
so what would it be entered in equation editor
mathslover (mathslover):
I didn't get you,, please explain!
OpenStudy (firejay5):
type the problem in fraction form of what we have left
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mathslover (mathslover):
hmn well it would be hard to say that I have :
\(\cfrac{\textbf{yet to come}}{3(m+2)(m-2)}\)
mathslover (mathslover):
we have to solve numerator now
mathslover (mathslover):
can u do that?
OpenStudy (firejay5):
wouldn't the numerator m + 2
mathslover (mathslover):
No! See : \(\cfrac{1}{(a+b)} + \cfrac{2}{(a-b)} = \cfrac{1(a-b) + 2(a+b)}{(a-b)(a+b)}\)
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OpenStudy (firejay5):
how does it work, you should + across
mathslover (mathslover):
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