CREDITS

Animation & Design: Jean-Pierre Louw – www.behance.net/Appel718

Narration: Lucy Billings

Script: Lucy Billings

You probably already know that quadratic equations look like this… We can also have quadratic inequalities… We use inequalities to show us a range of possible

values… which actually has many real life uses.

For example, I might use them to work out that I need to film a racecar between 10 and 15 seconds after the start of the race. And they’re used throughout finance, such as working out what loan you can afford based on your

expenditure.

We solve quadratic inequalities in pretty much the same way we solve quadratic equations, but also making use of the graph to help us work out which part we want… let’s have a look at an example. Solve it like you normally would… so factorise, quadratic formula or complete the square. This one factorises.

Notice how i’ve changed it to be equals now. Solve each bracket, x equals 3 and x equals negative 2. Sketch what this quadratic looks like… U shaped, crossing the x-axis at -2 and 3. It’s just a rough sketch to help yourself in answering the question, so don’t worry too much about it at all. Because we want where the quadratic is LESS THAN zero. We want this part of the graph – the part that is less

than 0 for y but also has the quadratic in.

This means the answer is x is greater than or equal to negative 2 but less than or equal to 3. Because we’ve shaded one joined region, the answer is one inequality.

It’s this inequality sign because that was in the question.

Because we have 2 separate regions shaded, this means we have 2 separate inequality answers. Where x is less than negative 4 And where x is greater than negative 2. Because the question was a “greater than” inequality, that’s what our answers are…No “or equal to” involved. And that’s all there is to solving quadratic

inequalities. You just need to do a little sketch of the graph, and work out the values from there.

SUBSCRIBE to the FuseSchool YouTube channel for many more educational videos. Our teachers and animators come together to make fun & easy-to-understand videos in Chemistry, Biology, Physics, Maths & ICT.

VISIT us at www.fuseschool.org, where all of our videos are carefully organised into topics and specific orders, and to see what else we have on offer. Comment, like and share with other learners. You can both ask and answer questions, and teachers will get back to you.

These videos can be used in a flipped classroom model or as a revision aid.

Find all of our Chemistry videos here:

https://www.youtube.com/watch?v=cRnpKjHpFyg&list=PLW0gavSzhMlReKGMVfUt6YuNQsO0bqSMV

Find all of our Biology videos here:

https://www.youtube.com/watch?v=tjkHzEVcyrE&list=PLW0gavSzhMlQYSpKryVcEr3ERup5SxHl0

Find all of our Maths videos here:

https://www.youtube.com/watch?v=hJq_cdz_L00&list=PLW0gavSzhMlTyWKCgW1616v3fIywogoZQ

Twitter: https://twitter.com/fuseSchool

Access a deeper Learning Experience in the FuseSchool platform and app: www.fuseschool.org

Follow us: http://www.youtube.com/fuseschool

Friend us: http://www.facebook.com/fuseschool

This Open Educational Resource is free of charge, under a Creative Commons License: Attribution-NonCommercial CC BY-NC ( View License Deed: http://creativecommons.org/licenses/by-nc/4.0/ ). You are allowed to download the video for nonprofit, educational use. If you would like to modify the video, please contact us: info@fuseschool.org

You must log in to post a comment.