Question

2 x la a doua = 7x + 1

Answer 1

faci (x+x)(x-x)-7x= 1

Answer 2

$2 {x}^{2} = 7x + 1$

$2 {x}^{2} - 7x - 1 = 0$

$a = 2$

$b = - 7$

$c = - 1$

$\Delta = {b}^{2} - 4ac$

$\Delta = {( - 7)}^{2} - 4 \times 2 \times ( - 1)$

$\Delta = 49 + 8$

$\Delta = 57 > 0 \: = > \exists \: x_{1} \: \neq \: x_{2}$

$x_{1,2} = \frac{ - b \pm \sqrt{\Delta} }{2a}$

$x_{1,2} = \frac{ - ( - 7) \pm \sqrt{57} }{2 \times 2}$

$x_{1,2} = \frac{7 \pm \sqrt{57} }{4}$

$x_{1} = \frac{7 + \sqrt{57} }{4}$

$x_{2} = \frac{7 - \sqrt{57} }{4}$