Question

factorise 729x^3-512y^3

Answer 1

hi friend!!

729x³-512y³

=(9x)³-(8y)³

we know that a³-b³=(a-b)(a²+b²+ab)

→(9x-8y)(81x²+64y²+72xy)

therefore, (9x-8y) and (81x²+64y²+72xy) are the factors.

I hope this will help u ;)

Answer 2

Hi,

Here is your answer !
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729x³ - 512y³

= 9³x³ - 8³y³

= (9x)³ - (8y)³

= (9x - 8y) [ (9x)² + (8y)² + (9x)×(8y) ]

= (9x - 8y) ( 81x² + 64y² + 72xy )

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Identity used :

(a³ - b³) = (a - b) (a² + b² + ab)