Question

решите алгебра 8 класс
квадратные уравнения
дам 35баллов

Answer 1

Ответ:

20) x1 = 4;  x2 = 3

19) x1 = 1/4;  x2 = -1/3

18) x1 = -8  x2 = 8

17) x = 0

Объяснение:

20) (x-2)^2 = 3x-8

x^2-4x+4 = 3x-8

x^2-4x+4-3x+8=0

x^2-7x+12 = 0

D = 49 - 48 = 1

x1 = (7+1)/2 = 4

x2 = (7-1)/2 = 3

19) 6x(2x+1) = 5x + 1

12x^2+6x = 5x+1

12x^2+x-1 = 0

D = 1 - 4 * (-12) = 1+48 =49

$\sqrt{49}$ = 7

x1 = (-1+7)/24 = 1/4

x2 = (-1-7)/24 = -1/3

18) x^2-64 = 0

x^2 = 64

x1 = -8  x2 = 8

17) 6x^2 = 0

x^2 = 0

x = 0