Question

How do you find `f(x+Yx)` for `f(x)=x^3 + 1`?

Answer 1

Replace `color(blue)(x)` in `f(color(blue)(x))=color(blue)x^3+1`
with `color(red)(x+Yx)` to get `f(color(red)(x+Yx))`

Explanation:

If `f(color(blue)x)=color(blue)x^3+1)`
then
`f(color(red)(x+Yx))=color(red)((x+Yx))^3+1`

`color(white)("XXX")=x^3+3x^2Y+3xY^2+y^3+1`