Math, asked by krazzy, 10 months ago

(27a cube +125 b cube) find using identity

Answers

Answered by priya8268

Answer:

27a³+135a²b+225ab²+125b³

Attachments:

krazzy: just try doing an example

KINGAMAN: Bro You have written a cube + b cube but the formula is of a+b whole cube

krazzy: try 3 sqaure plus 2 square and (3 plus 2) square

krazzy: u will get one as 13 and other one as 25

krazzy: both r different

krazzy: a cube plus b cube is equal to (a+b)(a square + ab+ b square)

krazzy: no

krazzy: (a+b) ( asquare - ab plus b square

krazzy: (a+b) the whole cube is equal to a cube + b cube+ 3ab( a + b)

krazzy: see .... both are different

Answered by pulakmath007

27a³ + 125b³ = (3a + 5b)(9a² – 15ab + 25b²)

Given :

The expression 27a³ + 125b³

To find :

Factorise the expression

Formula :

a³ + b³ = (a + b)(a² – ab + b² )

Solution :

Step 1 of 2 :

Write down the given expression

The given expression is

27a³ + 125b³

Step 2 of 2 :

Factorise the expression

27a³ + 125b³

$\sf = {(3a)}^{3} + {(5b)}^{3}$

$\sf = (3a + 5b) \{ \: {(3a)}^{2} - 3a.5b + {(5b)}^{2} \}$

= (3a + 5b)(9a² – 15ab + 25b²)

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