Answer with Step-by-step explanation:
We have to solve the equation:
[tex]x^4-9x^2+8=0[/tex]
let u=x²
u²-9u+8=0
⇒ u²-8u-u+8=0
⇒ u(u-8)-1(u-8)=0
⇒ (u-8)(u-1)=0
⇒ u=8 or u=1
⇒ x²=8 or x²=1
⇒ x=2√2 or x=-2√2 or x=1 or x=-1
Hence, Solution of [tex]x^4-9x^2+8=0[/tex] is:
x=2√2 ,-2√2,1 and-1
