Using Descartes' Rule of Signs 

this guy is the best, may all his wishes come true

This man right here, has made my math experience so much easier his simplistic style of teaching is awesome! Keep up the great work

this guy is my favorite person on earth, lord bless him

In case anyone was wondering why he had the "or subtract away an even number"... Remember roots can be positive, negative, or imaginary. Imaginary numbers come in conjugate pairs (one with a +, one with a - ). Think about the kind of answers you get with the quadratic formula when you get imaginary numbers, +/-. He didn't talk about imaginary numbers in this video, but that's where the minus some even number comes from.

you never fail me! your videos are Always a great help when I am reviewing for my final.

I love this teacher, he is awesome!

Missed this one, I have no regrets. I gained appreciation for mathematics first. This is a cool theorem and you explained it well, thankyou.

you explained this the best! thank you !!

Every other video I watched did not explain the possibilities like he did. Now I understand. I could never understand when they would say 3 or 1.... I was like, "where did the one come from?" Thanks

thank you so much ... you really helped me 😍❤

dear mr Burger, you are such a funny and innovative teacher, you are the best, thanks for helping me soooo much in math.

thank you for saving my gpa 🙏🏾

your amazing thanks so much

Thank You Sir, keep safe everyone. God Bless Us All Always.

Thank you soo much, now i can finally understand it well

Thank you so much!!

thank you so much for this

What about nonreal roots?

Thanks!!!!!!

thanks, didn't understand it from my textbook !

Omg thank you so much

Very helpful

Thank you sir

You're good

I'd never in a million years guess Descartes was pronounced without the S

Thanks so much but Im not a big fan of the sound the paper and marker makes

Hey, I'm a real person