Math, asked by Anonymous, 1 year ago

Urgennnnnnnnnnnnnnt!
Factorise: (2x+3y)³ - (2x-3y)³

Answers

Answered by TPS
234
Use the identity: a³ - b³ = (a - b)(a² + ab + b²)

(2x+3y)³ - (2x-3y)³
= [(2x + 3y) - (2x-3y) ][(2x-3y)² + (2x - 3y)(2x + 3y) + (2x + 3y)² ]
= [ 2x + 3y - 2x + 3y ][(4x² + 9y² - 12xy) + (4x² - 9y²) + (4x² + 9y² + 12xy) ]
= [6y][ 4x² + 9y² - 12xy + 4x² - 9y² + 4x² + 9y² + 12xy ]
= [6y][ 4x² + 4x² + 4x² + 9y² + 9y² - 9y² - 12xy + 12xy ]
= [6y][ 12x² + 9y²]
= 6y×3×(4x² + 3y²)
= 18y(4x² + 3y²)

Anonymous: You're not even watching the question.
TPS: what do you mean?
Anonymous: No..................................................................
Anonymous: It's the one that I wrote at first.
Anonymous: I replaced 54y square with a cube.
TPS: i know that but where did you get the 108 xy^2?
Anonymous: Shall I show the steps?
TPS: sure.
Anonymous: I'm typing it in the comments of the above answer.
Anonymous: check it there.
Answered by srikrishnacharyulu
54
I THINK THAT ANSWER IS 
54y^3+72x^2y

process= [(2x)^3+3(2x)^29(3y)+3(2x)(3y)^2+(3y)^3]-[(2x)^3-3(2x)^2(3y)+3(2x)(3y)^2-(3y)^2]

= [8x^3+36x^2y+54xy^2+27y^3-8x^3+36x^2y-54xy^2+27y^3

= 54y^3+72x^2y

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TPS: Nice!! you finally got it, so time is not wasted! ;)
Anonymous: whose shall I mark as brainliest?
Anonymous: can u help me in another problem?
TPS: The one which you think best should be marked as best!:)
I will try. give the link!
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