Factoring Quadratics - The Cross Method

In this video I go over a quick trick for factoring non-monic trinomials (quadratic scenarios where 'a' is not 1). This method is called The Cross Method and it's a quick trick - I still think it's important to understand how factoring works.

0:00 Intro
0:54 Example 1 (two positives)
2:53 Example 2 (pos. & neg.)
5:18 Example 3 (two negatives)
6:43 Example 4 (neg. & pos.)

[aungheinkhant-zemusashi]

This video is everything I need for the maths exam. THANKS!

[brandonfeng]

Wow, thank you so much. I was taught this a year ago but forgot how to do it, and was completely confused seeing other tutors break up the middle term. This makes things 10x faster.

[ruller]

Thanks for this, I missed the first like 3, 4 weeks of school and everybody else was taught this last year and I never understood how to use it.

[loganmcfarland]

This is super helpful, I completely forgot how to do this and now I remember, thanks!

[komaljeetkaur]

i had initial doubts regarding sign but all thanks to yu .All doubts cleared Grt vdio.
..keep it up

[DailyChallenges]

3:30 New meaning of wtf: what the factors

Edit: P.S. very clean and neat videos! Thank you :)

[Christofxzsc]

THANK U SO MUCH I GET THIS MUCH EASIER THAN MY TEACHER😭😭🙏 VERY HELPFUL FOR THE TEST TOMM😭😭

[anglez]

Thank you so much. This video has helped me make it way easier to calculate quadratic trinomials!

[_sindiswa]

this this, sir, i owe you my math marks❤

[manasvi]

thanks for the help! i was really confused at first

[s-megagaming]

Thanks for helping a Lot, many of the books doesn't completly explain the cross method THANKS!!

[mr.heisenberg]

Thank you Sir 👌👌👌 outstanding class 💯 you desese more subs

[thisarmywillalwaysstay]

Thank you so much for doing this video it was extremely helpful.

[salehajabeen]

hello sir do you think we will get marks if we do this ... i mean what about the working ?? and this doesn't apply for roots right? apart from it thank you for this :) it'll be really helpful for me if you answer this

[aryamansingh]

Thank you my math teacher is teaching this method and she thought it in a different way

[teacherasmith]

Is there ever an instance where the factors of the first number and the last number don’t work out to give us the middle number? What method could we use then?

[TienShan.]

FINALLY! I have found another educator properly explain the cross method. I learn this years ago and now I am teaching students how to do it properly. I actually list out all the factor pairs of the leading coefficient & constant term (the a & c terms), in the ax^2 + bx +c format. That way, my students don't have to recall which pair they have (or haven't) tried. I also teach them to pare down the factor pairs (ie, skipping over a pair of even factors if I am looking for an odd sum). They can also systematically exhaust all possibility and say the trinomial has no rational roots before they see the quadratic formula or the discriminant.
Here is my attempt with 55x^2 -373x + 630

[edmundlee]

Is this method only guess and check or is there an algebraic way to do this

[JustNeutral]

so its guess and check, no other way to not guess? :]
ive not rlly tried tbh, does the guessing not take that long as i think it is?
nonetheless, tysm!

[BoofGalls]

in 6:27, do we just forget about the negative sign in front of the 6? Does it not matter? (in the equation, not the answer)