Question

4Х
$4x ^{2} - 30x + 1 = 0$
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Answer 1

Ответ:

$\frac{15 - \sqrt{221}}{4};\ \ \ \frac{15 + \sqrt{221}}{4}$

Объяснение:

$4x^{2} - 30 x + 1 =0\\\\ a= 4,\ \ b=-30 ,\ \ c=1\\\\ D = b^2 - 4ac = ( - 30)^2 - 4\cdot4\cdot1 = 900 - 16 = 884\\\\\sqrt{D} =\sqrt{884} = \sqrt{4 \cdot 221} = 2\sqrt{221}\\\\ x_1=\frac{-b-\sqrt{D}}{2a}=\frac{30-2\sqrt{221}}{2\cdot4}=\frac{2(15-\sqrt{221}) }{8 }=\frac{15 - \sqrt{221}}{4}\\\\ x_2=\frac{-b+\sqrt{D}}{2a}=\frac{30+2\sqrt{221}}{2\cdot4}=\frac{2(15+\sqrt{221})}{8}=\frac{15 + \sqrt{221}}{4}$