Question

5x2+8-4=0 решите полное кв уравнения

Answer 1

$5 {x}^{2} + 8x - 4 = 0 \\ d = {8}^{2} - 4 \times 5 \times ( - 4) = 64 + 80 = 144 \\ x1 = \frac{ - 8 + 12}{2 \times 5} = \frac{4}{10} = 0.4 \\ x2 = \frac{ - 8 - 12}{2 \times 5} = \frac{ - 20}{10} = - 2$