Question

Решите уравнение x^2+5*x+3=0 и x^2-5*x-3=0

Answer 1

x^2+5*x+3=0

d = b^2 - 4ac = 5^2 - 4 × 1 + 3 = 25 - 12 = 13

$x1.2 = \frac{ - b( + - ) \sqrt{d} }{a {}^{2} } = \frac{ - 5( + - ) \sqrt{13} }{2}$

$x1 = \frac{ - 5 - \sqrt{13} }{2}$

$x2 = \frac{ - 5 + \sqrt{13} }{2}$

x^2-5*x-3=0

d = b^2 - 4ac = 5^2 - 4 × 1 ×(- 3 ) = 25 + 12 = 37

$x1.2 = \frac{ - b( + - ) \sqrt{d} }{a {}^{2} } = \frac{ - 5( + - ) \sqrt{37} }{2}$

$x1 = \frac{ - 5 - \sqrt{37} }{2}$

$x2= \frac{ - 5 + \sqrt{37} }{2}$