Example: Complex roots for a quadratic | Algebra II | Khan Academy

Complex Roots from the Quadratic Formula

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[trooperboot]

Shoutout to all the people grinding out there🏆

[bradwillard]

i have a final tomorrow and have no idea what is going on

[operationghostgaming]

thanx my teacher went over this once and it was only a matter of 2 and a half hours. I guess thats how algerbra honors works.

[skullkazor]

Thanks so much! I wasn't sure at first if I was able to involve the imaginary number i if the equation didn't already have it included somewhere. This helped me more than I could have possibly hoped for!

[ChriSportGuy]

A random non-real root disliked this video

[sleepysoul-zzz]

Thank you so much, Khan Academy. You have helped more people than you will ever know.

[thejonathan]

1759 views, only one person asks a question and only 1 other person thaks khan for his work.... what is this world coming to? THANK YOU SALMAN KHAN YOU ARE A HERO IN THE WORLD OF MATHIMATICS!!!!

[MikeMike-ycgg]

2:49

Square root of - 4

3:21

4:46

[faniSuarez]

How to convert it back to a quadratic?

[Omplata]

How do I get the equation if im initially given the complex roots ?

[thejonathan]

Im just wondering this because this is what I was just taught in school for the past week, but isnt it easyer instead of (+or-) just to have your new numbers looking like this (I will use 10 and 5 as examples) y=(x2+10x+25)-25+5 the 25 are the half b squred value inside and out of the brakets...

[MathCuriousity]

Why do we sometimes get extraneous solutions when using quadratic formula?

[thejonathan]

here is my version (S= squared) y=2xS-6x+5 > y=(2xS-6x)+5 > y=2(x-3)S+5 > b=-3 half b=-1.5 half b, S=2.25> y=2(x-3+2.25)S-2.25+5 > y=2(x-1.5)+2.75 and than thats the farthest you go.... and then to get the vertex you take V=1.5, 2.75... please correct me if im wrong.. BUT NOT ON MY SPELLING...

[element]

so, if (-b±sqrt(d))/2a = x, then (-b±sqrt(-d))/2a = xi

[qud_ratol]

What is the difference between real and nor real roots?

[mysticorange]

Formula inventors name is sridhara acharya who is an indian

[monkeyglocks]

at 8:06 can someone explain to me where this 6 is coming from because I can't figure it out.

[hellgod]

i dont understand why they cant teach us basic complex nos and put this concept in 10th class itself instead of putting the whole thing in 11th

[takayoutube]

It took me 30mins to figure out why (-1)^2 = -1 . since i^2=-1, (-i)^2 =-i x -i= i^2

[itsnethergamingboyz]

i understand everything till 3-i/2 but after that i don't understand what you are telling