Question

how do you find f(g(n)) if f(n)=3n-1 and g(n) = n^2 + 5. Please help i am totally confused

Answer 1

plug n^2 + 5 in f(n)

Answer 2

===> f(g(n))= 3(n^2 + 5)-1

Answer 3

Start with f(n)


f(n)=3n-1


Now replace EVERY copy of 'n' with g(n) like so


f(g(n))=3*g(n)-1


Now, because g(n) = n^2+5, this means that we can replace the "g(n)" on the right side with n^2+5 to get

f(g(n)) = 3(n^2+5)-1


Finally, expand and simplify as must as possible


f(g(n)) = 3(n^2+5)-1


f(g(n)) = 3(n^2)+3(5)-1


f(g(n)) = 3n^2+15-1


f(g(n)) = 3n^2+14