Răspuns :
x + 1 / x = 2
x² + 1 = 2x => x² - 2x = 1
x² - 2x - 1 = 0
a = 1
b = - 2
c = - 1
Delta = b² - 4ac
D = - 2² - 4 * 1 * ( - 1 )
D = 4 - 4 * ( - 1 )
D = 4 + 4
D = 8
X1 = ( - b - rad. D ) / 2a
X1 = 2 - 2 rad. 2 / 2 * 1
X1 = 2 - 2 rad. 2 / 2
X1 = 2 - rad. 2
X2 = ( - b + rad. D ) / 2a
X2 = 2 + 2 rad. 2 / 2 * 1
X2 = 2 + 2 rad. 2 / 2
X2 = 2 + rad. 2
Răspuns:
[tex]x + \frac{1}{x} = 2 \\x + \frac{1}{x} - 2 = 0 \\ \frac{ {x}^{2} + 1 - 2x}{x} =0 \\ \frac{ {(x - 1)}^{2} }{x} = 0[/tex]
Raportul dintre doua numere e 0 numai si numai daca numaratorul e 0.
Deci
[tex] {(x - 1)}^{2} = 0 \\ |x - 1| = 0 \\ x - 1 = 0 \\ x = 1[/tex]