Question

If x plus one upon x is 7 find the value of x cube + half x cube

Answer 1

Answer:

The numeric value of x^3 + 1 / x^3 is 322.

Step-by-step explanation:

It is given that the value of x plus one upon x is 7, it can be written as :

x + 1 / x = 7

Cube on both sides,

= > ( x + 1 / x )^3  = 7^3

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From the properties of expansion. we know : -

( a + b )^3 = a^3 + b^3 + 3ab( a + b )

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On the basis of the formula given above,

= > x^3 + 1 / x^3 + 3( x × 1 / x )( x + 1 / x ) = 343

= > x^3 + 1 / x^3 + 3( 1 )( 7 ) = 343

= > x^3 + 1 / x^3 + 21 = 343

= > x^3 + 1 / x^3 = 343 - 21

= > x^3 + 1 / x^3 = 322

Hence the numeric value of x^3 + 1 / x^3 is 322.