Question

If x - 1/x = 4 , then evaluate x^2 + 1/x^2

Answer 1

hey !~

squaring,

x^2+1/x^2=16-2

=14

ans!

thanks!

Answer 2

Step-by-step explanation:

$\boxed{given}$

$\boxed{x-1/x=4}$

$\underline{TOFIND}$

$x {}^{2} + \frac{1}{x {}^{2} }$

now taking x-1/x=4

squaring both sides

$(x - \frac{1}{x} ) {}^{2} = (4) {}^{2}$

$using(a - b) {}^{2} = a {}^{2} + b {}^{2} - 2ab$

$x {}^{2} + \frac{1}{x {}^{2} } - 2 = 16$

$x { }^{2} + \frac{1}{x {}^{2} } = 16 + 2$

$x {}^{2} + \frac{1}{x {}^{2} } = 18$