Question

25x^4-20x^2+3=0 = x= i sqrt3/5,-i sqrt3/5.

I used the method complete the square.

is this is correct

Answer 1

If you let y=x^2 then:
25*y^2 - 20*y +3 = 0
You can use the quadratic formula to solve. Your solution for y will really be for x^2. Take the square root of y values to get the x values.
I did not get any imaginary values. One answer (that I got) IS sqrt(3/5), but as a real number. So, I think you are on the right track.

Answer 2

The original factors very nicely into

(5y^2 - 3)(5y^2 - 1) = 0
so
y^2 = 3/5 or y^2 = 1/5
then y = ±√(3/5) or ±√(1/5)

Answer 3

Thanks

Answer 4

thanks