Question

$2x^{2} / 5 + 0,4x - \sqrt{2} = 0$

Answer 1

Resposta: (text)2×^(2)/5+0,4×=0(/text).

Answer 2

Oie, Td Bom?!

$\frac{2x {}^{2} }{5} + 0.4x - \sqrt{2} = 0 \\ \\ \frac{2x {}^{2} }{5} + \frac{2}{5} x - \sqrt{2} = 0 \\ \\ 2x {}^{2} + 2x - 5 \sqrt{2} = 0$

• $ax {}^{2} + bx + c = 0⟶x = \frac{ - b± \sqrt{b {}^{2} - 4ac } }{2a}$

$x = \frac{ - 2± \sqrt{2 {}^{2} - 4 \: . \: 2 \: . \: ( - 5) \sqrt{2} } }{2 \: . \: 2} \\ \\ x = \frac{ - 2± \sqrt{4 + 40 \sqrt{2} } }{4} \\ \\ x = \frac{ - 2±2 \sqrt{1 + 10 \sqrt{2} } }{4}$

$x = \frac{ - 2 + 2 \sqrt{1 + 10 \sqrt{2} } }{4} ⟶x = \frac{ - 1 + \sqrt{1 + 10 \sqrt{2} } }{2} \\ x = \frac{ - 2 - 2 \sqrt{1 + 10 \sqrt{2} } }{4} ⟶x = \frac{ - 1 - \sqrt{1 + 10 \sqrt{2} } }{2}$

S = $\left \{ x_{1} = \frac{ - 1 - \sqrt{1 + 10 \sqrt{2} } }{2} \: , \: x_{2} = \frac{ - 1 + \sqrt{1 + 10 \sqrt{2} } }{2} \right \}$

Att. Makaveli1996