Question

How do you factor `x^4+2x^2+1`?

Answer 1

`(x^4+2x^2+1) = (x^2+1)^2`

Explanation:

Temporarily replace `x^2` with `t` to get
`color(white)("XXX")t^2+2t+1`
which should be recognizable as `(t+1)^2`

Then reverse the replacement
`color(white)("XXX")(x^2+1)^2`