Maths Extension - Algebra (1 Viewer)

[Crosswinds]

Hiii.

Okay can someone please help me with this question? Keeping in mind you're speaking to someone who is mathematically challenged. I have a worked answer for it but I don't understand it.


Factorise fully:
(m+2n)³ + (m-2n)³


The answer is:
2m(m²+12n²)


The first line of working is:
(m+2n+m-2n)((m+2n)²-(m+2n)(m-2n)+(m-2n)²)

Whhhyy?


Sorry for the semi-public display of stupidity but this is eroding my will to live.

 

[khorne]

It's easy...Have you learnt cubes yet? Just think of (m+2n)^3 as a^3 and (m-2n)^3 as b^3

The standard form is then (a+b)(a^2 - ab + b^2), which is the first line of your working.

 

[Crosswinds]

Ohhhh yeaaaahhhh.

Um okie thanks.

Lol. Now I feel stupider.

 

[TBK11]

Hiii.

Okay can someone please help me with this question? Keeping in mind you're speaking to someone who is mathematically challenged. I have a worked answer for it but I don't understand it.


Factorise fully:
(m+2n)³ + (m-2n)³


The answer is:
2m(m²+12n²)


The first line of working is:
(m+2n+m-2n)((m+2n)²-(m+2n)(m-2n)+(m-2n)²)

Whhhyy?


Sorry for the semi-public display of stupidity but this is eroding my will to live.

ah i got a diffrent answer to this just started this so might be wrong check attachment

ended up with 2m^3+24mn^2

 

[gcchick]

It's the same answer dude, yours just isn't factorised.