Question

Решите неполное квадратное уравнение,помогите пожалуйста

1,3 и 5 примеры

Answer 1

6.6

1)

${x}^{2} - 5x = 0 \\ x(x - 5) = 0 \\ x_{1} = 0 \\ x - 5 = 0 \\ x_{2} = 5$

3)

$- 7 {x}^{?} + 1.8x = 0 \\ x( - 7x + 1.8) = 0 \\ x_{1} = 0 \\ - 7x + 1.8 = 0 \\ x = - 1.8 \div ( - 7) \\ x_{2} = \frac{18}{70}$

5)

$- 0.8 {x}^{2} - 9.2x = 0 \\ x( - 0.8x - 9.2) = 0 \\ x_{1} = 0 \\ - 0.8x - 9.2 = 0 \\ x = 9.2 \div ( - 0.8) \\ x_{2} = - \frac{23}{2}$

6.7

1)

${x}^{2} - 25 = 0 \\ {x}^{2} = 25 \\ x = + - \sqrt{25} \\ x_{1} = - 5 \\ x_{2} = 5$

3)

$- 7 {x}^{2} + 28 = 0 \\ - 7 {x}^{2} = - 28 \\ {x}^{2} = - 28 \div ( - 7) \\ {x}^{2} = 4 \\ x = + - \sqrt{4} \\ x_{1} = - 2 \\ x_{2} = 2$

5)

$- 0.8 {x}^{2} - 9.2 = 0 \\ - 0.8 {x}^{2} = 9.2 \\ {x}^{2} = 9.2 \div ( - 0.8) = - 11.5 \\ {x}^{2} < 0$

, значит нет корней уравнения.