Question

x² - 4x + |x² - 5| -1 =0

Answer 1

|x²-5|=-x²+4x+1

 

x²-5=-x²+4x+1 lub x²-5=x²-4x-1

2x²-4x-6=0 lub -4x+4=0⇒x=1

x²-2x-3=0

Δ=4-4*1*(-3)

√Δ=4

x=-1

x=3

 

x=-1 lub x=1 lub x=3

 

Answer 2

x^2 -4x +Ix^2 -5I -1 = 0

x^2 > 0, to Ix^2 -5I = x^2 -5

x^2 < 0, to Ix^2 -5I = -(x^2 -5) =5+x^2

 

x^2 -4x +x^2 -5 -1 = 0

2x^2 - 4x -6 = 0  I:2

x^2 -2x -3 = 0

D =b^2 -4ac

D =4 +12 =16

VD =4

x1 =(2 -4)/2 =-1

x2 =(2 +4)/2 =3

 

x^2 - 4x +5 -x^2 - 1 = 0

-4x =-4  I:(-4)

x =1

 

x =-1, v  x =1,  v  x =3