Question

Find all the roots. x^4-5x^2+4=0

Answer 1

solve
\[u^2-5u+4=0\] and then replace \(u\) by \(x^2\)

Answer 2

\[u^2-5u+4=0\]
\[(u-4)(u-1)=0\]
\[u=4,u=1\] are the first steps

Answer 3

then \(x^2=4\implies x=2\) or \(x=-2\) and \(x^2=1\implies x=1\) or \(x=-1\)

Answer 4

@satellite73 Thanks :) That really helped!!