Question

If ƒ(x ) = x 2 + 1 and g(x ) = 3x + 1, find 2 · ƒ(4).

Answer 1

@Nnesha

Answer 2

\(\large\color{purple}{ \displaystyle f(x)=x^2+1 }\)
\(\large\color{brown}{ \displaystyle g(x)=3x+1 }\)

To find \(2\cdot f(2)\) you don't need the \(g(x)\).
Just, plug in 2 instead of x into the \(f(x)\),
and then multiply the result times two.

Answer 3

4*

Answer 4

Ok, if I wanted to find: \(4\cdot f(3)\)
then this is what I would do:

\(\large\color{black}{ \displaystyle f(x)=x^2+1 }\)

Plug in 3 instead of x:
\(\large\color{black}{ \displaystyle f(\color{red}{3})=\color{red}{3}^2+1 }\)

I know that \(3^2=9\), so I can write that:
\(\large\color{black}{ \displaystyle f(3)=9+1 }\)

And then, obviously, 9+1=10, so this is what I get for \(f(3)\).
\(\large\color{black}{ \displaystyle f(3)=10 }\)

Now, I have to multiply:
I am asked to find \(4 \cdot f(3)\), and since I know that \(f(3)=10\),
I can just go ahead and apply that (substitute 10 for f(3) ):
\(\large\color{black}{ \displaystyle 4\cdot f(3)=4 \cdot 10 = 40 }\)

Answer 5

(hope this is a helpful example)

Answer 6

i got an answer that wasnt one of the options

Answer 7

what did you get ?

Answer 8

5.3

Answer 9

That is not possible

Answer 10

\(\large\color{black}{ \displaystyle f(x)=x^2+1 }\)
\(\large\color{black}{ \displaystyle f(4)=\bf ? }\)

Answer 11

i said i did it wrong then i redid it and got it right