Question

find solutions: x^4-2x^2-15=0

Answer 1

ok pretend that x^2=n

Answer 2

so n^2-2n-15=0, solve from there and then plug x^2 back into the equation at the end

Answer 3

i got (+/-) square root of 5 and (+/-) i square root 3

Answer 4

did you use the quadratice formula? if so then double check you work and that should be right