Question

Решите уравнения
x^2-3x=0
2x^2+9x+8=0
2x^2-9x-10=0

Answer 1

$x {}^{2} - 3x = 0 \\ x(x - 3) = 0 \\ x = 0 \\ x = 3 \\ 2x {}^{2} + 9x + 8 = 0 \\ d = 9 {}^{2} - 4 \times 2 \times 8 = 81 - 64 = 17 \\ x1 = \frac{ - 9 - \sqrt{17} }{4} \\ x2 = \frac{ - 9 + \sqrt{17} }{4} \\ 2x {}^{2} - 9x - 10 = 0 \\ d = 9 {}^{2} + 2 \times 4 \times 10 = 81 + 80 = 161 \\ x1 = \frac{9 + \sqrt{161} }{4} \\ x2 = \frac{9 - \sqrt{161} }{4}$