To find f(x) we subtract g(x) from (f+g)(x):
[tex]3 x^{2} +2x-1-(2x-2) \\ 3 x^{2} +2x-1-2x+2 \\ 3 x^{2} +1[/tex] Distribute the negative across the parentheses and then combine like terms. The 2x gets cancelled out and we are left with [tex]A. 3 x^{2} +1[/tex]
Hope that helps.
