Math, asked by aman122, 1 year ago

how to factorise 27 -125a cube-135a+225a square

Divyankasc: 27 - 125a³ - 135a + 225a

Divyankasc: = (3)³ + (-5a)³ + (3×3×3×-5a) + (3×3×-5a×-5a)

Divyankasc: That is in the form of (a-b)³ = a³ - b³ -3a²b + 3ab²

qais: 225a square is correct

Divyankasc: So, the answer is (3-5a)³

qais: and there will be minus in ur 2nd step before 3x3x3x-5a...right :)

Divyankasc: I have written minus

qais: ok ok..i got u :)

Answers

Answered by qais

288

27 - 125a³ -135a+ 225a²
=(3)³ - (5a)³ -3×3×5a(3 - 5a)
=(3-5a)³

Anonymous: both methods are correct ur mothed id come from mine

Anonymous: sry method

Anonymous: there in a square and b square aretake and put in bracket

Answered by mysticd

117

Answer:

27-125a³-135a+225a

= (3-5a)³

= (3-5a)(3-5a)(3-5a)

Step-by-step explanation:

Given 27-125a³-135a+225a

=3³+(-5a)³+3×3²×(-5a)+3×3×(-5a)²

= [3+(-5a)]³

/* By an algebraic identity:

$\boxed {x^{3}+y^{3}+3x^{2}y+3xy^{2}\\=(x+y)^{3}}$ */

=(3-5a)³

Therefore,

27-125a³-135a+225a = (3-5a)³

•••♪

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