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# Write the following cube in expanded form: (ii) (2a - 3b)^3

6.(ii) Write the following cube in expanded form:

(ii)    $(2a-3b)^3$

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Given is  $(2a-3b)^3$

We will use identity

$(x-y)^3=x^3-y^3-3x^2y+3xy^2$

Here,  $x= 2a \ \ and \ \ y= 3b$

Therefore,

$(2a-3b)^3=(2a)^3-(3b)^3-3.(2a)^2.3b+3.2a.(3b)^2$

$= 8a^3-9b^3-36a^2b+54ab^2$

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