F (1) = 3f (1) = 3 and f (n) = 2f (n-1) + 3

f (n) = 2f (n-1) + 3

then find the value of f (3)

f (3) = 21

Step-by-step explanation:

f (1) = 3

f (n) = 2f (n-1) + 3

n=2

f (2) = 2f (2-1) + 3

f (2) = 2f (1) + 3

f (2) = 2*3+3

f (2) = 6+3

f (2) = 9

n=3

f (3) = 2f (3-1) + 3

f (3) = 2f (2) + 3

f (3) = 2*9+3

f (3) = 18+3

f (3) = 21