Question

4x^2-x-1=0 помогите!!​

Answer 1

Ответ:

$4 {x}^{2} - x - 1 = 0 \\ d = b {}^{2} - 4ac = 1 - 4 \times 4 \times ( - 1) = 1 + 8 = 9 \\ x1 = \frac{ - b - \sqrt{d} }{2a} = \frac{1 - 3}{8} = - \frac{1}{4} \\ x2 = \frac{ - b + \sqrt{d} }{2a} = \frac{1 + 3}{8} = \frac{1}{2}$