Question

x^4-9x^2+20=0
solve this quadratic equation​

Answer 1

Here is your solution: Hope it helps....

=>x^4-5x^2-4x^2+20=0

=>x^2(x^2-5)-4(x^2-5)=0

=>(x^2-4)(x^2-5)=0

Thus, x=2 or root 5