Răspuns :
x + 1/x = 11
(x + 1/x)² = 121
x² + 2 + 1/x² = 121
x² + 1/x² = 119
(x + 1/x)² = 121
x² + 2 + 1/x² = 121
x² + 1/x² = 119
Ridicam la pătrat expresia
x+1/x=11
(x+1/x)^2=11^2
x^2+2*x*1/x+1/x^2=121
x^2+2+1/x^2=121
x^2+1/x^2=121-2
x^2+1/x^2=119
x+1/x=11
(x+1/x)^2=11^2
x^2+2*x*1/x+1/x^2=121
x^2+2+1/x^2=121
x^2+1/x^2=121-2
x^2+1/x^2=119