Question

2y^2 - 8y - 4 =0 погомите пожалуйста!

Answer 1

$2 {y}^{2} - 8y - 4 = 0 \\ d = {8}^{2} - 4 \times 2 \times ( - 4) = 64 + 32 = 96 \\ y_{1} = \frac{8 + \sqrt{96} }{2 \times 2} = \frac{8 + 4 \sqrt{6} }{4} = \frac{4(2 + \sqrt{6}) }{4} = 2 + \sqrt{6} \\ y_{2} = \frac{8 - \sqrt{96} }{2 \times 2} = \frac{8 - 4 \sqrt{6} }{4} = \frac{4(2 - \sqrt{6}) }{4} = 2 - \sqrt{6}$