Question

Daca x € lui R*,astfel incat x+1 supra x=4,atunci aflati valoarea sumei x patrat plus unu supra x patrat

Answer 1

$\frac{x+1}{x}=4$
x+1 = 4x
$\frac{ x^{2}+1}{ x^{2}}$
$\frac{(x-1)(x+1)}{ x^{2} } = \frac{(x-1)* 4x}{ x^{2}} = \frac{ 4x^{2}-4x}{ x^{2} }$
simplifici pe $x^{2}$ si rezultatul e 4-4x

Answer 2

x+1/x=4
(x+1/x)²=4²
x²+2×x×1/x+1/x²=16
x²+2+1/x²=16 =>
x²+1/x²=14