Answer
a) 98; b) 49; c) 4; d) 4.
Work Step by Step
We are given the functions:
$f(x)=2x$
$g(x)=3x^2+1$
a) $(f\circ g)(4)=f(g(4))=f(3(4^2)+1)=f(49)=2(49)=98$
b) $(g\circ f)(2)=g(f(2))=g(2(2))=g(4)=3(4^2)+1=49$
c) $(f\circ f)(1)=f(f(1))=f(2(1))=f(2)=2(2)=4$
d) $(g\circ g)(0)=g(g(0))=g(3(0^2)+1)=g(1)=3(1^2)+1=4$