'Show That' Quadratic Formula Volume Question GCSE Level 7

This video is all about the Quadratic formula and forms part of the playlist of the same name. I've also added to the playlist on GCSE higher revision.

The question is aimed at around level 7 GCSE mathematics:

The volume of the cuboid is 51 cm cubed. Show that 2xsquared - 4x - 51 = 0


I hope the video helps and please do leave a comment - thanks!

or click here for a limited 50% discount!:

The course contains around 3 hours of video, quizzes and a copy of my book 'How to get an A in maths.' All the way through to GCSE and just in time for revision.

Visit playlists to help you get more from your studies

GCSE - everything you need to know to get great grades

How to solve linear equations

.. and many more.

Please also add any suggestions for future videos on my Google+ page

[TrivialBroker]

Just finished my final GCSE maths paper and i just wanted to say thanks because honestly you have no idea how much these videos have helped me.

[jalicorabisa]

Keep this videos going. They are short and helpful.

[designanddevelop]

I was looking on a mark scheme for a question, and I understand everything but how it jumped from step 1 -> step 2:

step 1: x - 1 + (4x / (2x -1)) = 4
step 2: (2x -1)(x-1) + 4x = 4(2x -1)

It may be easier to write this down on paper and thanks for all your help!

[ben_harrop]

Hi Mr Deacon i just want to say thanks so much for help today!! :)

[dumomkweli]

hi and thank you i find your content very helpful so do you mind doing a video on circle theorems and working out the radius please

[edsivak]

any chance you could create a video on loci, GCSE. thank you

[stephenbarker]

hi simon can you help me with a log equation please LOG5 ( N sqaured + 20N ) = 3 how do i work this out

[kzskychirblx]

Can you solve harder "show that" examples? I am weak on this topic.

[shutup]

Thank you so much for the video it really helped !!

[sarapogue]

Hi, this is a question about one of your older videos but I thought to comment on ur new one in the hope I would get a reply .
If I have two rectangles which are similar, I have two areas and one length .
Once I've found out the constant, which in this case is 2.25 what do I do next . To find the height of the larger rectangle ?

[stanfordp]

Could you solve even more advanced questions like this one?
This is something I'm really struggling at.

[demar]

Sir can you do questions on combination

[aliceatkins]

Could this type of question come up on the non-calculator paper?

[tals]

When do you know that you have to use the quadratic equation?

[stephenbarker]

hi simon can you check something for me the edexcel 2016 papers have been released can you tell me if i would have lost marks on q 2 on calculator paper for leaving answer as 37 over 4 thanks

[wt]

Hello, I'm hoping you get back on time I have an important exam on Wednesday and the only thing im struggling with is constructing equations, such as Jane has £40 and Kate has £50. kate gives Jane £x. Jane now has twice as much as kate. How much did kate give Jane. I would be very grateful if you got back to me as quick as possible or even possibly make a video or just reply back, many thanks.