Question

If x+1/x=5, then find x^3 +1/x^3

Answer 1

Hey User,

Here is Your answer.

GIVEN.

$x+\frac{1}{x}=5$.....1

TO FIND:-

$x^3+\frac{1}{x}^3$

Cubing eq.1 BOTH the sides.

$(x+\frac{1}{x})^3=x^3\frac{1}{x^3}+3×x×\frac{1}{x}(x+\frac{1}{x})$

$\bf\pink{PUT\:THE\:GIVEN\:VALUES}$

$(5)^3=x^3+\frac{1}{x^3}+3(5)$

$125=x^3+\frac{1}{x^3}+15$

$125-15=x^3+\frac{1}{x^3}$

$110=x^3+\frac{1}{x^3}$

Thank You!.