Algebraic Proof - GCSE Mathematics Algebra Proof Question 4 Level 6

This video is all about GCSE Mathematics algebraic proof and forms part of the playlist Proof - GCSE Mathematics. The question deals with:

Prove that (2n + 3)^2 – (2n – 3)^2 is a multiple of 8 for all positive integer values of n.

You need to be careful with the negative sign in the middle - although it's useful to learn the method as this type of question is quite popular.

Proof uses algebra and is usually on a GCSE non calculator question paper.

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

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[transportflick]

Finally... after several attempts in class this video was very simple to understand. Was able to do a similar proof question in an exam today.

[seyitanodufalu]

I actually understand algebraic proofs now.
Yes, thank you so much for your help, it is greatly appreciated

[kieranayling]

these questions always stumped me and now i can answer any of these in like 2 mins thanks so

[aminahagha]

All your videos are extremely helpful thank you so much ☺

[thomash]

Thanks again! This is something I have always struggled with but I have a much better grasp now, this question is identical to the question I was looking for help with haha.

[priya]

(3:36) does it matter which way I put it around if I put 3(8n) instead would I sill get full marks?

[mischawyss]

Other Solution:
(2n+3)^2-(2n-3)^2
= [(2n+3)+(2n-3)]* [(2n+3)-(2n-3)]
=[4n]*[6]
=24n
=8*3n

[stephenbarker]

i expand second bracket then multiply it by minus 1

[AJITHKUMAR-kcll]

can we do it with (a^2) + (b)^2 = (a+b)×(a-b)