Question

12x+2x^2=31 срочнооо

Answer 1

$12x + 2x {}^{2} - 31 = 0 \\ 2x {}^{2} + 12x - 31 = 0 \\ d = 12 {}^{2} - 4 \times 2 \times ( - 31) \\ d = 144 + 248 = 392 \\ \\ x = \frac{ - 12 + \sqrt{392} }{4} \\ \sqrt{392} = 14 \sqrt{2}$

$x1 = \frac{ - 12 + 14 \sqrt{2} }{4} = \frac{ - 6 + 7 \sqrt{2} }{2}$

$x2 = \frac{ - 12 - 14 \sqrt{2} }{4} = \frac{ - 6 - 7 \sqrt{2} }{2}$

$x1 = \frac{ - 6 - 7 \sqrt{2} }{2} \\ \\ x2 = \frac{ - 6 + 7 \sqrt{2} }{2}$