Question

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

Answer 1

Answer:

${(x + \frac{1}{x}) }^{3} = {5}^{3} \\ {x}^{3} + \frac{1}{ {x}^{3} } + 3(x + \frac{1}{x}) = 125 \\ {x}^{3} + \frac{1}{ {x}^{3} } + 3(5) = 125 \\ {x}^{3} + \frac{1}{ {x}^{3} } = 110$