Question

If f(x) = x 2 + 1 and g(x) = 3x + 1, find 2·f(4). can anyone help me with this problem

Answer 1

Okay so for this problem you are given two equations: \[f(x)=x ^{2}+1\]
(I'm assuming) and \[g(x)=3x+1\] When they ask for f(4), you are being asked to solve f(x) when x=4. So, wherever there is an "x" in your equation, simply replace it with the number 4.
In this case, \[f(4)=4^{2}+1\] or \[f(4)=4\times4+1=17\]
Now, then 2f(4) is simply 2 times the function f(x) when x=4.
So, \[2\times f(4)=2\times17=34\]
I hope this helps!!