First let's find g(2) .
g(x) = x2 + 3
Plug in 2 for every x in the equation.
g(2) = 22 + 3
Simplify the right side of the equation.
g(2) = 4 + 3
g(2) = 7
Second let's find f(7) .
f(x) = 2x - 4
Plug in 7 for every x in the equation.
f(7) = 2(7) - 4
Again simplify the right side of the equation.
f(7) = 14 - 4
f(7) = 10
So now we have found...
f( g(2) ) = f( 7 ) and f( 7 ) = 10 so f( g(2) ) = 10