Квадратные уравнения решите уравнения: x^2-4x+3=0 x^2+9x=0 7x^2-x-8=0 2x^2-50=0

X^2 - 4x + 3 = 0
D = b^2 - 4ac = 16 - 12 = 4 = 2^2
x1 = ( 4 + 2)/ 2 = 3
x2 = ( 4 - 2) / 2 = 1

x^2 + 9x = 0
x( x + 9)=0
x = 0
x + 9 =0
x = - 9

7x^2 - x - 8 = 0
D = b^2 - 4ac = 1 + 224 = 225 = 15^2
x1 = ( 1 + 15) / 14 = 16/14 = 8/7 = 1 целая 1/7
x2 =( 1 - 15)/ 14 = - 1

2x^2 - 50= 0
2x^2 =50
x^2 = 25
x= 5
x = - 5

1. D=16-12=4, x1= (4+2)/2, x1=3
X2=(4-2)/2, X2=1
2. x(x+9)=0, x1=0, X2= -9
3. D=1+224=225, x1=(1+15)/14,
x1=16/14=8/7=1.14, X2=(1-15)/14
X2= -1
4. 2(x^2-25)=0, 2(x-5)(x+5)=0
x1-5=0, x1=5, X2+5=0, X2= -5