need help with quadratic equation?

Question

i need help solving this quadratic equation.
x^4 - x^2 - 4 = 0

Answer 1

X^4 - X^2 - 4=0
x^2 - X - 2 = 0 (square root the whole equation)
(x + 1) (x - 2) = 0

thus, x = -1 , x = 2

Answer 2

This is actually a quartic equation. It will have 4 roots.
It is quadratic in x². So let u = x² and we must solve
u² - u -4 = 0.
Since b²-4ac is 17, we cannot solve this by factoring,
so let's use the quadratic formula:
We get u = ½(1 + √17)
or u = ½(1 - √17).
Then the 4 roots of the original equation are
x = √ ½(1 + √17)
x = -√ ½(1 + √17)
x = √ ½(1 - √17)
x = -√ ½(1 - √17).
Hope that helps!

Answer 3

x^4 - x^2 - 4 = 0
(x^2 - 2)(x^2 +2)=0
x^2 -2 =0 x^2+2=0
x^2=2 x^2= -2
x= square root 2 or 2^(1/2) x= not vaild b/c it is the square root of -2.

x= 2^(1/2) or sqaure root 2

Answer 4

x = 1.6