Реши уравнение х²=2х+8

Question

Реши уравнение х²=2х+8

Comments

X1=-2 X2=4

Answer 1

х² = 2х + 8

х² - 2х - 8 = 0

D = (-2)² - 4 × 1 × (-8) = 4 + 32 = 36

x1 = ( 2 + 6 ) / 2 = 4

x2 = ( 2 - 6 ) / 2 = -2

Ответ : х1 = 4 ; х2 = -2

Answer 2

x^2-2x-8=0

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

x(x+2)-4(x+2)=0

(x-4)(x+2)=0

x-4=0, x+2=0

x=4, x=-2