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(Barré) #1

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a

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1 1
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3

=^23 ]


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2 3 323 [

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a

a

= 2 3 3 2 3


3 3
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= 8 ˜ 3 3  6 3


= 24 3  6 3


= 18 3 (proved)
Activity : 1. If x  2 , what is the value of 27 x^3  54 x^2  36 x 8?


  1. If ab 5 and ab 6 , find the value of a^3 b^3  4 (ab)^2.

  2. If x 5  3 , find the value of^33
    1
    x


x .

Exercise 3⋅ 2


  1. Find the cube with the help of the formulae :


(a) 2 x 5 (b) 2 x^2  3 y^2 (c) 4 a 5 x^2 (d) 7 m^2  2 n (e) 403 (f) 998
(g) 2 ab 3 c (h) 2 x 3 yz



  1. Simplify :


(a) ( 4 a 3 b)^3  3 ( 4 a 3 b)^2 ( 2 a 3 b) 3 ( 4 a 3 b)( 2 a 3 b)^2 ( 2 a 3 b)^3


(b) ( 2 xy)^3  3 ( 2 xy)^2 ( 2 xy) 3 ( 2 xy)( 2 xy)^2 ( 2 xy)^3


(c) ( 7 x 3 b)^3 ( 5 x 3 b)^3  6 x( 7 x 3 b)( 5 x 3 b)


(d) (x 15 )^3 ( 16 x)^3  3 (x 15 )( 16 x)


(e) (abc)^3 (abc)^3  6 (bc){a^2 (bc)^2 }


(f) (mn)^6 (mn)^6  12 mn(m^2 n^2 )^2


(g) (xy)(x^2 xyy^2 )(yz)(y^2 yzz^2 )(zx)(z^2 zxx^2 )


(h) ( 2 x 3 y 4 z)^3 ( 2 x 3 y 4 z)^3  12 x{ 4 x^2 ( 3 y 4 z)^2 }



  1. If ab 5 and ab 36 , what is the value of a^3 b^3?

  2. If a^3 b^3 513 and ab 3 , what is the value of ab?

  3. If x 19 and y  12 , find the value of 8 x^3  36 x^2 y 54 xy^2  27 y^3.

  4. If a 15 , what is the value of 8 a^3  60 a^2  150 a 130?

  5. If a 7 and b  5 , what is the value of

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