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any of you fags good at college level algebra? how the hell do

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Thread replies: 60
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any of you fags good at college level algebra?
how the hell do you solve this shit?
it involves complex numbers and multiplying.

there are no examples anywhere on the internet about this. my text book is useless. youtube tutorials dont explain this format.

im stuck as fuck. pls halp /b/ trying to make my life better with education. this is my third time taking college algebra. im a dingus i know. im at work right now and cant go tutoring during the days.
>>
>>720110132
bump
>>
-21i
>>
>>720110273
but how doe.
>>
the answer is 35 + 14i because it would turn into 14i -35i squared and i squared is technically negative 1 so u multiply negative 1 by negative 35 and get positive 35
>>
https://www.mathsisfun.com/numbers/complex-numbers.html diy faggot
>>
35+14i
>>
14i -35i(square)
>>
whoever posted -21i is retarded
>>
14i - 35i Squared
>>
>>720110430
u cant leave i squared
>>
>>720110459
no i represents a negative
>>
>>720110349
so why isnt 14i just -14 then?
and wouldnt i just do 35 -14 for an actual number for an answer? 21??
>>
14i+35
>>
>>720110132

7i(2-5i)

=14i-35i²
=14i-(35*-1) (because i² = -1)
=14i+35
>>
>>720110459
say u wanna square root -25. it would be 5i do to the negative
>>
College level algebra? This shit is taught at highschool and the easiest subject in the math class compared to others.
>>
Dude, just use Khan Academy, they have everything there.
>>
14i+35
>>
14i - 35i^2
14i - 35(-1)
14i + 35
I think. It has been a long time...
>>
35+14i
>>
>>720110551
u cant do anything with just i, but if u have i squared then that number which has i squared needs to be multiplied by negative 1
>>
>>720110583
i only passed geometry in highschool.
i did my other 3 years of math in 2months on a credit recovery program where i googled literally every question.

i am not a great student. but im trying to change that.
>>
>>720110132
Nigga distribute

7i(2-5i) = 7i*2 + (-5i*7i)
>>
that is not even college lvl, i had that in high school ... basic stuff you need to know:
sqrt(-1) = i ...or i^2 = -1
x*(a+b) = x*a + x*b

then:
7i*(2-5i) =
7i*2 - 7i*5i =
14i - 35*(i)^2 =
14i + 35 done
>>
2, -35i
>>
i is root over -1, which is imaginary. i squared is -1, which is real
>>
>>720110335
you multiply 2 and -5i seperately by 7i

7i*2=14i
7i*(-5i)=-35i

14i-35i=21i

but I doubt this is the correct number anyhow. complex numbers probably have something more in them but cba to look it up neither am I in school anymore
>>
>>720110633
Just use Khan Academy m8, that shit works
>>
>>720110132

35 + 14 i
>>
>>720110622
this.

14i + 35
>>
>>720110132
Algebra is a high school class.....if you take algebra in most colleges it doesnt even count as a credit it means your dumbass needs it to get to basic math courses
>>
>>720110699
dubs of the truth
>>
5 + 2i idiots
>>
>>720110706
7i*(-5i)=-35i²

i*i = i²
i² = -1

-35*i²
= (-1)*35*i²
= (-1)*35*(-1)
=(-1)*(-1)*35
=35
>>
>>720110682
xa23#$-54te^?(67×47+÷<₩%21)/23:,;*wakawaka = this is math

You have 3 apples. You pick 3 more. Now you have 6 = this is real life
>>
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>>720110706

>you multiply 2 and -5i seperately by 7i
>7i*2=14i
>7i*(-5i)=-35i
>14i-35i=21i

Idiot.
>>
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>>720110850
nice one fam
>>
>>720110723
I failed my remedial math in college...3 times. Then i cheated with a math solving website and got a C (the math solving website didnt know how to solve alot of math)
>>
>>720110631
fuck dude thank you so much. i understand it now.
>>
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>any of you fags good at college level algebra?
>college level algebra
>that
'Murican education, everyone.
>>
>>720110390
i^2 = -1 so its just 35+14i
>>
>>720110132
Did you just right that down randomly or was it an actual question that was proposed?

The expansion of the expression you have written indeed solves as 35+14i, which looks a lot like one of the complex roots of a quadratic equation (i.e., the result of applying the "{-b +/- sqrt(b^2.....}/2a" formula they teach you in high school). Before simplifying with complex number i the result would have been "35 + sqrt(-196)" = "35 + sqrt(196).sqrt(-1) = "35 + 14i"

The other root would be "35 - 14i".

These values have some "real" meaning to people like electrical engineers (I'm a chemical engineer) who use them in things like Bode plots for frequency analysis and phase shift shit... I don't understand it.

You can transform the complex solutions back to real numbers by assuming that all solutions to an ODE will have the form y=e^... and applying Eulers formula, but I haven't done that in 15 years.
>>
>>720110583
No it isn't. Not in Burgerland
>>
Given 2 complex numbers:
1: Z = a + b•i
2: S = c + d•i

S•Z = (a•c - b•d) + (a•d + b•c) i

^this form is obtained by distributing one term into the other than simplifying

In your case:
Z = 0 + 7i
and
S= 2 + (-5)i
>>
14i+35
>>
>>720110877
You numnut. i*i = i^2. So....

7i*2=14i
7i*-5i=-35i^2
And i^2=-1
-35*-1=35
Answer is,
14i+35
>>
>>720110682
this guy knows his shit
>>
>>720110877
do you even know what 2+2 is you fucking retard? go back to 6th grade
>>
Since i^2 is -1 (imaginary number)
It comes out to 14i-35i^2
35i^2 = positive 35
35-14i is the simplification.
>>
>>720110132
>college level algebra
!?!?!?!?!?
da fugggg!!!!
this is not college algebra. it's high school one.
and your equation is deliberately misspelled.
OP again you are a faggot.
>>
-21i^2
>>
>>720110132
wait, this thread is still alive wtf stop bumping he had his answer 5 min after he asked let it die now
>>
>>720110132
Treat i like a variable that equals -1 when squared.
>>
4chung academy
>>
>>720110349
This is the answer
>>
>>720110568
There
>>
>>720110132
You can write it as
7i*2-7i*5i
Multiply the numbers and you get
14i -35i*i (this is i²)
By definition i=sqrt(-1), so i² =sqrt(-1)²=-1
This leaves you at
14i-35*(-1) = 14i + 35
The answer is
>14i + 35
>>
>>720118065
Yep.

Just distribute and substitute -1 for i^2. Easy. Did it in my head.

OP should not go into electrical engineering...
>>
>>720110132
Dont worry op Complex numbers is a short chapter that in real life nobody uses except for maybe a few engineering fields
Thread posts: 60
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