Given: f(x) = 3x2 +4
To find f(x+2), wherever you see x in the orginal given equation, you substitute (x+2) as such:
f(x+2) = 3(x+2)2 + 4, which equals: 3(x2 + 2x + 2x + 4) + 4 = 3(x2 + 4x + 4) + 4 = 3x2 + 12x +12 + 4,
finally adding the constants, the final answer:
3x2 + 12x + 16
Part 2:
f(x) = 3x2 + 4 (given)
then, for f(2), replace x with 2, which gives us:
f(2) = 3(2)2 + 4 = 3(4) + 4 finally, f(2) = 12 + 4 = 16
adding the two functions per the question [ f(x) + f(2) ] gives us
3x2 + 4 + 16 = 3x2 +20
Hope this helps,
kind regards