Question

solve
9x^4-21x^2+10=0

Answer 1

This is long one! :(

Answer 2

Set u = x^2 and then you have a quadratic equation in u, as u^2 = x^4

Answer 3

factors of 90 that add to -21.....

Answer 4

are you following what I said?

Answer 5

discriminant is 81, a perfect square, so it should factor.

Answer 6

it does factor

Answer 7

but just use quad formula after a while.

Answer 8

ok, i got +/-sqrt 5/3 and +/- sqrt 2/3 ???

Answer 9

\[x= \frac{ 21 +- 9}{18}\]

Answer 10

(3x^2 - 2)(3x^2 - 5) = 0, yes.

Answer 11

so pixie yes