Question

If x+1/x = 5 find the value of x^3 +1/x^3. pls solve​

Answer 1

Answer:

1) solve x+1/x = 5

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

$x + 1 = 5x$

$x - 5x = - 1$

$- 4x = - 1$

$x = \frac{ -1}{ - 4}$

$x = \frac{1}{4}$

2) solve x³+1/x³

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

substitute x = 1/4 into the expression

$( \frac{1}{4} ) {}^{3} + \frac{1}{( \frac{1}{4}) {}^{3} }$

$\frac{1}{64} + \frac{1}{ \frac{1}{64} }$

$\frac{1}{64} + \frac{64 \times 1}{1}$

$\frac{1}{64} + 64$

$\frac{4097}{64} \: or \: 64.02$