Question

7. Найдите корни уравнения
(2х + 5)/2 - (х^2 +10х)/2=1
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Answer 1

Ответ:

$\frac{2x+5}{2}-\frac{x^2+10x}{2}=1\;\;|*2\\\\2x+5-x^2-10x=2\\\\-x^2-8x+5=2\\\\-x^2-8x+3=0\\\\D=b^2-4ac=64+12=76\\\\x_1=\frac{-b+\sqrt{D}}{2a}=-\frac{8+\sqrt{76}}{2}=-\frac{2(4+\sqrt{19})}{2}=-4-\sqrt{19}\\\\x_2=\frac{-b-\sqrt{D}}{2a}=-\frac{8-\sqrt{76}}{2}=-\frac{2(4-\sqrt{19})}{2}=\sqrt{19}-4$