Answer:
2n+20
Step-by-step explanation:
Twice a number = 2 x n (2n)
20 more than = +20
Altogether its 2n+20
f(5) means to replace x in the equation with 5 then solve.
f(x) = x^2 +2x
f(5) = 5^2 + 2(5)
f(5) = 25 +10
f(5) = 35
The answer is D)35