Question

И можно решение примеров пожалуйста
40 баллов​

Answer 1

Ответ:

$1. \: x^{2} - \frac{7}{6} x + \frac{1}{3} = 6 {x}^{2} - 7x + 2 = 0 \\ d = 49 - 4 \times 6 \times 2 = 1 \\ x1 =( 7 + 1) \div 2 \times 6 = \frac{8}{12} = \frac{2}{3} \\ x2 = \frac{1}{2} \\ \frac{x2}{x1} = \frac{1}{2} \times \frac{3}{2} = \frac{3}{4}$

2

$(x + 5)(x + 6) = {x}^{2} + 11x + 30$

3.

$x + y = 28 \\ {x}^{2} + {y}^{2} = {20}^{2} \\ x = 28 - y \\ ( {28 - y)}^{2} + {y}^{2} = 400 \\ 784 - 56y + {y}^{2} + {y}^{2} - 400 = 0 \\ 2 {y}^{2} - 56y + 384 = 0 \\ {y}^{2} - 28y + 192 = 0 \\ d = 784 - 768 = {4}^{2} \\ x1 = \frac{28 - 4}{2} = 12 \\ x2 = 16$

ответ: 16

5.

$\frac{2x - {x}^{2} }{2} = x + \frac{1 - 3x}{4} \\ \frac{2(2x - {x}^{2}) }{4} - \frac{4x}{4} - \frac{1 - 3x}{4} = 0 \\ 4x - 2 {x}^{2} - 4x - 1 + 3x = 0 \\ 2 {x}^{2} - 3x + 1 = 0 \\ d = 9 - 8 = 1 \\ x1 = \frac{3 + 1}{4} = 1 \\ x2 = \frac{1}{2} \\ \frac{x1 + x2}{2} = \frac{ \frac{2}{2} + \frac{1}{2} }{2} = \frac{3}{4} = 0.75$