Sal factors x²-3x-10 as (x+2)(x-5) using the sum-product form: (x+a)(x+b)=x²+(a+b)x+a*b.
Watch the next lesson:
Missed the previous lesson?
High School Math on Khan Academy: Did you realize that the word “algebra” comes from Arabic (just like “algorithm” and “al jazeera” and “Aladdin”)? And what is so great about algebra anyway? This tutorial doesn’t explore algebra so much as it introduces the history and ideas that underpin it.
About Khan Academy: Khan Academy is a nonprofit with a mission to provide a free, world-class education for anyone, anywhere. We believe learners of all ages should have unlimited access to free educational content they can master at their own pace. We use intelligent software, deep data analytics and intuitive user interfaces to help students and teachers around the world. Our resources cover preschool through early college education, including math, biology, chemistry, physics, economics, finance, history, grammar and more. We offer free personalized SAT test prep in partnership with the test developer, the College Board. Khan Academy has been translated into dozens of languages, and 100 million people use our platform worldwide every year. For more information, visit www.khanacademy.org, join us on Facebook or follow us on Twitter at @khanacademy. And remember, you can learn anything.
For free. For everyone. Forever. #YouCanLearnAnything
Subscribe to Khan Academy’s High School Math channel:
Subscribe to Khan Academy:
source
now can we get this in English please?
why is this the only way i understand math guys
Did you do FOIL backwards for (x+a) and (x+b)
Wouldn’t it be x^2 + bx + ax + ab then x^2 (b + a)x +ab?
WHERE ALL THE SUBSCRIBERS
I genuinely don't feel as though this is beginner friendly it's very complex this was messy.
Where did the other x go in the ax + bx when you (a+b)x … im guessing since they are times by the same x you only need one but it just doesn’t feel right to lose it without using it or am I misinterpreting this?
hate my life
why doesn't this channel have 20m subs?
Not sure I like the idea of guessing what the numbers are. It doesn't feel right to have something like this where you have to solve an equation by process of elimination….is there no mathematical way to solve these types of questions?
There may be situations where the numbers aren't single digit numbers….am I supposed to then just brainstorm over what 'a' and 'b' equal? Surely there is a better way to do this. It seems like really bad practice to do things in such a manner.
It's like in programming when people use Magic Numbers without bothering to explain what they represent….then at some point someone else has to fix a bug but they are going through your code and they come across it and have to spend a stupid amount of time just puzzling over what the value represents. If things aren't properly explained they cost people valuable time.
I love your content
yeah but its pink not magenta
Ummmm
Awesome
hi delson
whos here 4 ms barry
|
/
Who's here from Mingo
I am so happy I could cry, thank you for your help!
x^2-3x-10 => x^2-5x+2x-10 => x(x-5)+2(x-5) => (x-5)(x+2)
I'm sorry, but this isn't right. It doesn't obey the Girard Relations of sum and product.
nice job!