Question

Пожалуйста помогите решить!! Квадратные уравнения дам 100 баллов

Answer 1

Общий вид квадратного уравнения:

$a {x}^{2} + bx + c = 0$

1.

$a = 3\\ b = - 5\\ c = 0$

$3 {x}^{2} - 5x = 0$

2.

$b = c = - 2$

$- 2x - 2 = 0$

3.

$a = - 5 \\ c = 7$

$- 5 {x}^{2} + 7 = 0 \\ {x}^{2} = \frac{7}{5} \\ x_1 = \sqrt{ \frac{7}{5} } = \frac{ \sqrt{35} }{5} \\ x_2 = - \frac{ \sqrt{35} }{5}$

4.

$a = 3 \\ b = 5$

$3 {x}^{2} + 5x = 0 \\ x(3x + 5) = 0 \\ x_1 = 0 \\ \\ 3x + 5 = 0 \\ x_2 = - \frac{5}{3}$

5.

1)

${x}^{2} = 3x \\ {x}^{2} - 3x = 0 \\ x(x - 3) = 0 \\ x1 = 0 \\ x - 3 = 0 \\ x_2 = 3$

2)

${x}^{2} + 2x - 3 = 2x + 6 \\ {x}^{2} + 2x - 3 - 2x - 6 = 0 \\ {x}^{2} - 9 = 0 \\ {x}^{2} = 9 \\ x_1 = 3 \\ x_2 = - 3$

3)

$3 {x}^{2} + 7 = 12x + 7 \\ 3 {x}^{2} - 12x = 0 \\ 3x(x - 12) = 0 \\ x_1 = 0 \\ x - 12 = 0 \\ x_2 = 12$