Consider the functions f(x) = 3x2 + 1 and g(x) = x + 3. What is the value of f[g(−1)]?

7

37

13

12

Question

Consider the functions f(x) = 3x2 + 1 and g(x) = x + 3. What is the value of f[g(−1)]?

 7

 37

 13

 12

anonymous · Answer

find g(-1) so -1+3 aka -2, then use that value in F(x) so then F(-2) which is i assume 3(-2)^2+1. so 3(4)+1 or 13.

anonymous · Answer

you could also form a function FoG by taking what g(x)= and plug that right side into the x value of the f(x) function

anonymous · Answer

FoG= (3)(x+3)^2 +1

anonymous · Answer

3x + 9^2 + 1
3x + 81 + 1
3x + 82?

I'm confused

anonymous · Answer

you have to take (x+3)^2 first, order of operations, therefore you get x^2+6x+9. that substitutes back in so (3)(x^2+6x+9) +1 simplify it's 3x^2+18x+28. plug in x=-1
you get 3-18+28.. aka 13

anonymous · Answer

oh ok now i understand