Answer:
Explanation:
Think of it as taking the place of y. f(n) is slightly more informative than y.
y = x^2 + 5x + 4 Now let f(x) = y
f(x) = x^2 + 5x + 4 Let x = 2. That is f(x)
f(2) = x^2 + 5x + 4 That means wherever you see an x, put a 2
f(2) = 2^2 + 5*2 + 4 Put 2 in for x
f(2) = 4 + 10 + 4 expand the right side and add.
f(2) = 18