Answer:
(f+g)(x) = 60x + 400
Step-by-step explanation:
Given :
Amount in account A:
f(x) = 20x + 100
Amount in account B :
g(x) = 40x + 300
Total amount in Account A and B:
f(x) + g(x) = (20x + 100) + (40x + 300)
(f+g)(x) = (20x + 40x) + (100 + 300)
(f+g)(x) = 60x + 400
