Let's start with what we know:
[tex]2 x^{2}+3x+1 [/tex]
And we are trying to put it into this form:
[tex](? +/-?)(? +/- ?)[/tex]
Here is what it would look like:
[tex](2x + 1)(x + 1)[/tex]
You can check you work by using the FOIL method (first, outer, inner, last)