Answer:
±2
Step-by-step explanation:
This is a biquadratic equation, we must turn it into a quadratic one first before we solve it. So, let's say that x⁴ = y², therefore
[tex]y = \sqrt{x} [/tex]
and we turn it into the following quadratic equation:
y² - y - 2 = 0
then we solve it the way we solve a normal quadratic equations and find the roots:
D = 1 + 8 = 9
y1,2 = 1 ± 3 = 4, -2
[tex] \sqrt{x} = y[/tex]
We cannot find the square root of -2, so the solutions are only -2 and 2(because square root of 4 is equal to ±2)