Квадратнi рiвняння 8 класс. 2x²-3x-2 = 0 -6x-7x-1 = 0 x²-8x+12 = 0 (2x-5)(x+2) = 18 x²+7x = 0 2x²-11x = 0 -8x² = 0 3x²-6 = 0

1.d= (-3)^2 - 4 * 2 * - 2= 9+16=25

X1= 3+5/2*2=2

X2= 3-5/2*2= - 2/4= - 1/2

2. D= (-7)^2 - 4* -6 * - 1= 49 - 24=25

X1= 7+5/2*-6=12/-12= - 1

X2= 7-5/2* -6= 2/-12= - 1/6

3. D=(-8)^2-4*1*12=64-48=16

X1= 8+4/2=6

X2=8-4/2=2

4.2x +4x - 5x-10=18

X - 10-18=0

X=28

5.x(x+7)=0

X=0 и х+7=0

Х= - 7

6.х(2х-11)= 0

Х=0 и 2х-11=0

2х=11

Х= 11/2

7.- 8х^2=0 | /(-8)

Х^2=0

Х=0

8. 3х^2=6

Х^2= 2

Х1= 1

Х2 = -1