## anonymous one year ago Any help would be great: Function Notation If ƒ(x ) = x 2 + 1 and g(x ) = 3x + 1, find 2 · ƒ(4).

1. misty1212

HI!!

2. anonymous

Hi

3. misty1212

are you looking for $2\times f(4)$?

4. anonymous

Those values are subbed into the expression

5. anonymous

*equation

6. misty1212

there is not $$g$$ in this your main job is to find $f(4)=4^2+1$

7. misty1212

then multiply the result by 2

8. misty1212

you got that?

9. misty1212

$f(x)=^2+1\\ f(4)=4^2+1=17\\ 2f(4)=2\times 17$

10. anonymous

So 34. Why would you not add g of x?

11. misty1212

you asked for $2f(4)$right?

12. misty1212

got no $$g$$ in it

13. anonymous

That is where I reached my snag there was no x value so I assumed you simplified.

14. misty1212

lol there is no such thing as "simplify"

15. misty1212

add, subtract, multiply, divide, combine like terms, reduce to lowest terms, write in simplest radical form etc. but not "simplify"

16. anonymous

Great so I just have to solve for F(X)?

17. anonymous

My original question was just what was on my paper.

18. anonymous

So another example. If ƒ(x ) = x 2 + 1 and g(x ) = 3x + 1, find [ƒ(4)] 2. Would just be 257?

19. anonymous

x^2 and [f(4)] ^ 2

20. beginnersmind

well f(4) is 17. So [f(4)]^2 is 17^2.

21. beginnersmind

Or did you change the definition of f(x) to f(x) = x^2? Then [f(4)]^2 = (4^2)^2 = 16^2 = 256