Question 708364
{{{X^4 - 8x^2 = -16}}}
Add 16 to both sides
x^4 - 8x^2 + 16 = 0
Can be factored to
(x^2 - 4)(x^2 - 4) = 0
then we have
x^2 = 4
x = +/-{{{sqrt(4)}}}
two solutions
x = +2
x = -2
:
Graphically
{{{ graph( 300, 200, -6, 6, -10, 20, x^4 - 8x^2 + 16) }}}