Let f(x) = 5x - 1 and g(x) = x2 + 2.
Find (f o g)(3).

( f ∘ g ) ( x ) = 10 x − 3

Step-by-step explanation:

Just plug the formula for  g ( x )  into the formula for  f ( x ) (so replace  x  in the formula for  f ( x ) with what  g ( x ) equals), then simplify:

( f ∘ g ) ( x ) = f ( g ( x ) ) = f ( 2 x − 1 ) = 5 ( 2 x − 1 ) + 2 = 10 x − 5 + 2 = 10 x − 3 .