Question

Решить квадратное уравнение
1)25-9х²=0;
2)2х²-7х+3=0
3)-5х²-4х+33=0

Answer 1

2x²-7x+3=0
D=25
x1=8 x2=-4.5

Answer 2

1)
$25- 9 {x}^{2} = 0 \\ 9 {x}^{2} = 25 \\ {x}^{2} = \frac{25}{9} \\ x_{1} = - \frac{5}{3} = - 1 \frac{2}{3} \\ x_{2} = \frac{5}{3} = 1 \frac{2}{3}$
2)
$2 {x}^{2} - 7x + 3 = 0 \\ d = 49 - 4 \times 2 \times 3 = 25 \\ x_{1} = \frac{7 - 5}{4} = \frac{1}{2} \\ x_{2} = \frac{7 + 5}{4} = 3$
3)-5х²-4х+33=0
$- 5 {x}^{2} - 4x + 33 = 0 \\ d = 16 - 4 \times ( - 5) \times 33 = \\ 16 + 660 = 676 \\ x_{1} = \frac{4 - 26}{ - 10} = 2.2 \\ x_{2} = \frac{4 + 26}{ - 10} = - 3$