Question

if x-1/x=5,then find the value of x³-1/x³
pls answer this question ​

Answer 1

Given:-

☆Value of (x-1/x) is 5

To find:-

☆Value of (x³-1/x³)

Solution:-

=>Cubing both the sides in the equation x-1/x=5,we get:-

=>(x-1/x)³=(5)³

We know that (a-b)³=a³-b³-3ab(a-b)

=>x³-1/x³-3×x×1/x(x-1/x)=125

=>x³-1/x³-3(5)=125

=>x³-1/x³-15=125

=>x³-1/x³=125+15

=>x³-1/x³=140

Thus,value of x³-1/x³ is 140.

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Answer 2

Step-by-step explanation:

Given:-

☆Value of (x-1/x) is 5

To find:-

☆Value of (x³-1/x³)

Solution:-

• =>Cubing both the sides in the equation x-1/x=5,we get:-

=>(x-1/x)³=(5)³

• We know that (a-b)³=a³-b³-3ab(a-b)

=>x³-1/x³-3×x×1/x(x-1/x)=125

=>x³-1/x³-3(5)=125

=>x³-1/x³-15=125

=>x³-1/x³=125+15

=>x³-1/x³=140

• Thus,value of x³-1/x³ is 140.

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hope this helps you!!

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