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OpenStudy (anonymous):
OpenStudy (anonymous):
OpenStudy (anonymous):
i think i just neeed to do the last 4 steps its asking at the bottom
OpenStudy (anonymous):
can anyone help or understand how to do that?
OpenStudy (xapproachesinfinity):
what you think u should be?
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OpenStudy (xapproachesinfinity):
any ideas?
OpenStudy (xapproachesinfinity):
oh there two pages last 4 you are reffering to page 2 right?
OpenStudy (anonymous):
its all one problem
OpenStudy (xapproachesinfinity):
okay! first pages looks like an example to me
OpenStudy (anonymous):
i think i need to answer the 4 questions at the bottom of pg 2
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OpenStudy (xapproachesinfinity):
anyways we are doing this \(\sqrt{(x^2-x)+7}=2(x^2-x)-1\)
1) is about the u
OpenStudy (xapproachesinfinity):
any idea?
OpenStudy (anonymous):
there is no u there, but in pg 11 it says let u= t^2-3t is that right?
OpenStudy (xapproachesinfinity):
it say what would u represent i may reading this incorrectly lol
OpenStudy (xapproachesinfinity):
they want you to suggest a u for that equation
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OpenStudy (anonymous):
idk im very confused i dont see a U?? :S
OpenStudy (xapproachesinfinity):
no there is no u in the problem!
what they are telling you is do substitution instead of solving for x we solve for a new variable u
but we need first to make some kind of substitution
if you looked at the first page you have they give you an example
OpenStudy (xapproachesinfinity):
i think you didn;t read what that page is saying otherwise you would be confused what u is lol
OpenStudy (xapproachesinfinity):
because that first page explains it all!
OpenStudy (anonymous):
i did read it.
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OpenStudy (xapproachesinfinity):
lol! okay no problem
so we need to do substitution to some variable u
I'm speaking of this equation now \(\sqrt{(x^2-x)+7}=2(x^2-x)-1\)
OpenStudy (xapproachesinfinity):
this equation looks a mess for now that's why we do u to have only one good looking variable
OpenStudy (anonymous):
so we need to replace (x^2-x) with u right
OpenStudy (xapproachesinfinity):
so we can solve easily
ah yes you are catching good going so far
OpenStudy (xapproachesinfinity):
\(\sqrt{u+7}=2u-1\) letting u=x^2-x yes
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OpenStudy (xapproachesinfinity):
now we can solve for u before we go back to x
OpenStudy (xapproachesinfinity):
following?
OpenStudy (anonymous):
yea
OpenStudy (xapproachesinfinity):
\(\sqrt{u+7}=2u-1 \Longrightarrow u+7=(2u-1)^2\)
OpenStudy (xapproachesinfinity):
agree with this step or no?
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OpenStudy (xapproachesinfinity):
i took square of both sides
OpenStudy (anonymous):
to get rid of the sqrt, yea
OpenStudy (xapproachesinfinity):
good!
so now \(u+7=4u^2-4u+1 \Longrightarrow 4u^2-5u-6=0\)
OpenStudy (xapproachesinfinity):
we got a quadratic!
OpenStudy (xapproachesinfinity):
can we factor that!
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OpenStudy (anonymous):
wait
OpenStudy (xapproachesinfinity):
yes! any questions
OpenStudy (anonymous):
to get 4u^2 -5u-6, you just did -u-7 from both sides right?
OpenStudy (xapproachesinfinity):
yes!
OpenStudy (anonymous):
and then we need to factr that to (4u+3)(u-2)?
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OpenStudy (xapproachesinfinity):
now we factor to \((u-2)(4u+3)=0\)
OpenStudy (xapproachesinfinity):
yes excellent
OpenStudy (anonymous):
and use zpp?
OpenStudy (xapproachesinfinity):
solve for u
what is zpp lol never heard this haha
OpenStudy (anonymous):
zero product property lol
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OpenStudy (xapproachesinfinity):
i guess you mean u-2=0 or 4u+3=0
u=2 or u=-3/4
OpenStudy (anonymous):
yep
OpenStudy (xapproachesinfinity):
eh i see i never named anyhing it just makes sense to me with no name haha
OpenStudy (xapproachesinfinity):
now we solved for u but we still not finished for x
OpenStudy (xapproachesinfinity):
remember that we let u=x^2-x right
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OpenStudy (anonymous):
so for the first question its u= *3/4 and u=2 right
OpenStudy (xapproachesinfinity):
so we have \(x^2-x=2 ~~or~~ x^2-x=-3/4\)
OpenStudy (xapproachesinfinity):
oh no
first question to just answer u=x^2-x that is it
OpenStudy (xapproachesinfinity):
we are actually doing all those 4 question in one go
OpenStudy (anonymous):
ohh okay
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OpenStudy (xapproachesinfinity):
once we finish you put it in order 1 put what we did
2 put what we did
OpenStudy (xapproachesinfinity):
here i went to answer those as one question lol
they supposed to be one it is just that they want you to understand it part by part
OpenStudy (anonymous):
okay
OpenStudy (xapproachesinfinity):
2 we did we wrote the equATION WITH ONLY U
OpenStudy (anonymous):
gotcha
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OpenStudy (xapproachesinfinity):
3 we did we solved for u
u=2 u=-3/4
OpenStudy (xapproachesinfinity):
we are in 4 now :)
OpenStudy (xapproachesinfinity):
\(x^2-x=2 ~~or x^2-x=-3/4 \) we solve this now
OpenStudy (xapproachesinfinity):
two quadratic equations
OpenStudy (xapproachesinfinity):
\(x^2-x-2=0 ~~~or ~~~ 4x^2-4x+3=0\)
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OpenStudy (xapproachesinfinity):
looks good to you?
OpenStudy (anonymous):
no lol
OpenStudy (xapproachesinfinity):
may be i wen too fast haha
x^2-x=2
x^2-x-2=0 after subtracting 2 from both ssides
OpenStudy (anonymous):
how did you get 4x^2-4x+3
OpenStudy (xapproachesinfinity):
the other one x^2-x=-3/4 ===> 4(x^2-x)=-3 (multiplied 4 both sides)
4x^2-4x=-3
4x^2-4x+3=0 added 3 to both sides
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OpenStudy (xapproachesinfinity):
clear now i guess haha
OpenStudy (xapproachesinfinity):
i just wanted to have a nice format i dislike fractions haha
OpenStudy (xapproachesinfinity):
good or nor good?
OpenStudy (anonymous):
i was just trying to understand it sorry, im a slow learner lol i got it tho
OpenStudy (anonymous):
i got it
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OpenStudy (xapproachesinfinity):
hmm you are good learner as i see it :)
OpenStudy (anonymous):
aw thanks aha :))
OpenStudy (xapproachesinfinity):
we solve \(x^2-x-2=0 \Longrightarrow (x+1)(x-2)=0\)
OpenStudy (xapproachesinfinity):
this one 4x^2-4x+3=0 does not have real solutions
OpenStudy (xapproachesinfinity):
so we just solve (x+1)(x-2)=0
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OpenStudy (xapproachesinfinity):
zpp lol
OpenStudy (anonymous):
x=1 and 2
OpenStudy (anonymous):
-1,+2
OpenStudy (xapproachesinfinity):
yes great job
OpenStudy (xapproachesinfinity):
that for step 4 and we are good!
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