Question

h(x)=2x and g(x)= 3x²+1 what is h(g(x))

Answer 1

$(h(g(x)) = 2(3 {x}^{2} + 1) \\ (h(g(x)) = 6 {x}^{2} + 2$

Answer 2

You can think like this:
If y=g(x)=3x²+1
h(g(x))=h(y)=2y=2g(x)=2(3x²+1)
=6x²+2