You can simplify this by just multiplying it out. I like to use FOIL, going to every term and multiplying it with every other term. Let's do this:
[tex](x+1+i)(x+1+i) = (1+i)(x^2+x+xi) = (i)(x^2+x+xi) [/tex]
Next step:
[tex](i)(x^2+x+xi) = x^2i+xi+xi^2[/tex]
We know that: i² = -1 because √-1 × √-1 = -1. So:
[tex]x^2i+xi+x(-1)[/tex]
Your final answer:
[tex]x^2i+xi-x[/tex]
