Question

x²+18x-3=0 решите пожалуйста

Answer 1

$x {}^{2} + 18x - 3 = 0 \\ d = b {}^{2} - 4ac \\ D = 18 {}^{2} - 4 \times 1 \times ( - 3) \\ \\ D = 336 \\ x = \frac{ - b + - \sqrt{D} }{2a} \\ x1 = \frac{ - 18 +4 \sqrt{21} }{2} = - 9 - 2 \sqrt{21} = - 18.2 \\ x2 = \frac{ - 18 - 4 \sqrt{21} }{2} = - 9 + 2 \sqrt{21} = 0.2$

Answer 2

Ответ:

$x_{1} = - 9 - 2 \sqrt{21} . \\ x_{2} = - 9 + 2 \sqrt{21} .$

Объяснение:

х² + 18х - 3 = 0 ;

D = 18² - 4 · 1 · (-3) = 324 + 12 = 336 = (4√21)² ;

x_(1,2)=(-18±4√21)/2=(2(-9±2√21))/2=-9±2√21.