Help please due tomorrow

If f(x)=-x^2+6x-1 and g(x)=3x^2-4x-1,find(f+g)(x)

Suppose you are choosing a 6-digit personal access code. this code is made up of 4 digits chosen from 1 to 9, followed by 2 letters chosen from a to z. any of these digits or letters can be repeated. find the total number of personal access codes that can be formed. 492,804 341,172 39,917,124 4,435,236

Is experimental probibilty the same as the observed frequency in math? i need the answer asap!