Question

Daca x+1/x=3,calculati x la puterea a 2-a+1/x la puterea a 2-a

Answer 1

$x+ \frac{1}{x} =3 \\ \\ (x+ \frac{1}{x} )^2=3^2 \\ \\ x^2+ \frac{2x}{x} + \frac{1}{x^2} =9 \\ \\ x^2+2+ \frac{1}{x^2} =9 \\ \\ x^2+ \frac{1}{x^2} =7$