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Mathematics 11 Online
OpenStudy (matlee):

How do u factor this?

OpenStudy (matlee):

OpenStudy (matlee):

This is also for limits

OpenStudy (freckles):

well you want to get rid of the compound fraction multiply top and bottom by 3(3+x) this is the lcm of the bottoms of the mini-fractions

OpenStudy (matlee):

lcm? means highest degree?

OpenStudy (freckles):

least common multiple

OpenStudy (matlee):

least common uhm

OpenStudy (matlee):

oh

OpenStudy (matlee):

So do i multiply the 1's too?

OpenStudy (freckles):

you just multiply top and bottom by 3(3+x) like this: \[\frac{x}{\frac{1}{3+x}-\frac{1}{3}} \cdot \frac{3(3+x)}{3(x+3)} =\frac{x \cdot 3(3+x)}{(\frac{1}{3+x}-\frac{1}{3}) \cdot 3(x+3)} \\ =\frac{3x(3+x)}{\frac{1}{3+x} \cdot 3(x+3)-\frac{1}{3} \cdot 3(x+3)} \text{ by distributive property } \\ =\frac{3x(3+x)}{\frac{3(x+3)}{3+x}-\frac{3(x+3)}{3}}\]

OpenStudy (matlee):

wow how did you do it so fast it was taking me or ever to type

OpenStudy (matlee):

Ok uhm

OpenStudy (freckles):

i'm a computer

OpenStudy (freckles):

we are programmed to be faster

OpenStudy (freckles):

anyways I hope you see why we did this

OpenStudy (matlee):

Oh wow so you typedit all out?

OpenStudy (freckles):

(x+3)/(x+3)=1 and 3/3=1

OpenStudy (matlee):

Ok yes i see it so now i cross them out?

OpenStudy (freckles):

yes i did

OpenStudy (freckles):

yes

OpenStudy (freckles):

you will compound fraction go bye bye

OpenStudy (matlee):

i got 3-x+3 on the bottom after corssing about bottom fractions

OpenStudy (freckles):

well that isn't totally right I think you should have gotten 3-(x+3)

OpenStudy (matlee):

oh yes

OpenStudy (freckles):

3-x-3

OpenStudy (matlee):

-x

OpenStudy (freckles):

\[\frac{3x(3+x)}{3-(x+3)}=\frac{3x(3+x)}{-x}\]

OpenStudy (freckles):

one more thing can happen

OpenStudy (matlee):

ok awesome so i can uhm cross out the x?

OpenStudy (freckles):

yes because I assume you are taking the limit to x=0 (which means x cannot be zero so we can cancel out the x/x part)

OpenStudy (matlee):

Yes, holy crap how did you know

OpenStudy (matlee):

i need to learn math

OpenStudy (freckles):

lol you said it had something to do with limits and we couldn't plug in 0 at first because we had issue

OpenStudy (matlee):

Oh because there is a negative

OpenStudy (matlee):

oh yes haha good thinking

OpenStudy (matlee):

Ok so we cant crouss out the 0?

OpenStudy (freckles):

the 0?

OpenStudy (matlee):

Hi Ganshie

OpenStudy (matlee):

I mean the X

OpenStudy (freckles):

since x approaches 0 (this means x isn't 0 we only approach 0) so yes you can cross out the x's that is you can use x/x is 1

OpenStudy (freckles):

you should get -3(3+x)

OpenStudy (freckles):

as x approaches 0

OpenStudy (matlee):

wait but i thought we cross out the X

OpenStudy (freckles):

so now we can direct sub since this function is continuous at x=0

OpenStudy (matlee):

oh nvm

OpenStudy (freckles):

we did

OpenStudy (matlee):

so 9+x/-1

OpenStudy (freckles):

\[\frac{3x(3+x)}{3-(x+3)}=\frac{3\cancel{x}(3+x)}{-\cancel{x}} \]

OpenStudy (matlee):

9+3x/-1

OpenStudy (freckles):

3(3+x)=9+3x so you have (9+3x)/-1

OpenStudy (freckles):

right on

OpenStudy (matlee):

Thanks

OpenStudy (freckles):

with the ( ) of course but yeah i know what you meant

OpenStudy (matlee):

Yeah, lol Wait do you know how to program C++?

OpenStudy (freckles):

no i was not a computer if i was i bet i could c++ I lied I'm sorry :p

OpenStudy (matlee):

Lol, your not a computer programmer?

OpenStudy (freckles):

no

OpenStudy (freckles):

nor a computer

OpenStudy (matlee):

oh lol but anyways your still fast , lol yes i know your not a computer

OpenStudy (matlee):

I wish you did you could help me with C++!

OpenStudy (freckles):

lol haha i thought i fooled ya

OpenStudy (matlee):

Lol i woulda been like your not?!?! Ok so what now with tihs 9+3x/-1

OpenStudy (freckles):

you can also write it as -(9+3x)

OpenStudy (matlee):

Oh ok

OpenStudy (freckles):

or write it as -9-3x

OpenStudy (matlee):

So do i just plug any number to X? until it reaches 0?

OpenStudy (freckles):

but remember if you do as x approaches 0 you still need to plug in 0

OpenStudy (matlee):

So the answer is -9

OpenStudy (matlee):

Woo awesome i was trying to figre out how to get there

OpenStudy (freckles):

\[\lim_{x \rightarrow 0} \frac{x}{\frac{1}{3+x}-\frac{1}{3}}=\lim_{x \rightarrow 0}(-9-3x)=-9-3(0)\]

OpenStudy (matlee):

Lol ok thanks! I have a test tommorow and i gottal earn them all today -sad-

OpenStudy (freckles):

good luck on your test and your learning

OpenStudy (matlee):

Thanks !!

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