Question

$a) {5x}^{2} + 4x - 1 = 0 \\ b) {2x}^{2} - x - 3 = 0$
решить квадратное уравнение по формуле
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Answer 1

А)

$d = b {}^{2} - 4ac$

$d = 4 {}^{2} - 4 \times 5 \times ( - 1) = 36$

$x1 = \frac{ - 4 + 6 }{10} = \frac{1}{5 } = 0.2$

$x2 = \frac{ - 4 - 6}{10} = - 1$

Б)

$d = 1 {}^{2} - 4 \times 2 \times ( - 3) = 25$

$x1 = \frac{1 + 5}{4} = \frac{3}{2} = 1.5$

$x2 = \frac{1 - 5}{4} = - 1$