Question

5x^2-(10+√7)x+2√7=0 Решить

Answer 1

Ответ:

Объяснение:

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Answer 2

$5x^2-(10+\sqrt7)\, x+2\sqrt7=0\\\\D=\underbrace{(10+\sqrt7)^2}-40\sqrt7=\underbrace {100+20\sqrt7+7}-40\sqrt7=\underbrace {100-20\sqrt7+7}=\\\\=(10-\sqrt7)^2\\\\x_1=\dfrac{10+\sqrt7-(10-\sqrt7)}{10}=\dfrac{\sqrt7}{5}\\\\\\x_2=\dfrac{10+\sqrt7+(10-\sqrt7)}{10}=2$