X1,2=-1+-sqrt(2)
Объяснение:
x^2+2x=t
(t+2)(t-4)+5=0
t^2-2t-3=0
D=4+12=16
Sqrt(D)=4
T1,2=2+-4/2=1+-2
x^2+2x+3=0. x^2+2x-1=0
D<0. D=8
Sqrt(D) =2sqrt(2)
(х²+2х+2)(х²+2х-4)=-5
х²+2х-1 = t
(t + 3)(t - 3) = - 5
t² - 9 = -5
t² = 4
t = +- 2
1/ t =2
х²+2х-1 = 2
х²+2х-3 = 0
D = 4 + 12 = 16
x12 = (-2 +- 4)/2 = -3 1
2/ t = -2
х²+2х-1 = -2
х²+2х+1 = 0
(x + 1)² = 0
x = -1
ответ x = {-3, -1 , 1 }
X1,2=-1+-sqrt(2)
Объяснение:
x^2+2x=t
(t+2)(t-4)+5=0
t^2-2t-3=0
D=4+12=16
Sqrt(D)=4
T1,2=2+-4/2=1+-2
x^2+2x+3=0. x^2+2x-1=0
D<0. D=8
Sqrt(D) =2sqrt(2)
X1,2=-1+-sqrt(2)
(х²+2х+2)(х²+2х-4)=-5
х²+2х-1 = t
(t + 3)(t - 3) = - 5
t² - 9 = -5
t² = 4
t = +- 2
1/ t =2
х²+2х-1 = 2
х²+2х-3 = 0
D = 4 + 12 = 16
x12 = (-2 +- 4)/2 = -3 1
2/ t = -2
х²+2х-1 = -2
х²+2х+1 = 0
(x + 1)² = 0
x = -1
ответ x = {-3, -1 , 1 }