Ne vom folosi de fomulele:
(a + b)² = a² + 2ab + b²
(a - b)² = a² - 2ab + b²
x - (1/x) = 10
Ridicam relatia la patrat:
(x - (1/x))² = 100
x² - 2 + (1/x²) = 100
Acum vom scrie expresia in asa fel incat sa o putem reduce la un binom:
Am adaugat 4 in ambii membri:
x² + 2 + (1/x²) = 104
(x + (1/x))² = 104
x + (1/x) = √104 = 2√26
